krypted.com

Tiny Deathstars of Foulness

Migrating from macOS Mail Server is going to be one of the stranger migrations you might do. Why? Unless you’re moving to basically a custom build of the same tools used in macOS Server (which you’d do by forklifting /Library/Server/Mail/ into a postfix environment and putting the various components Apple changed at compile-time back together), the process for moving to a modern system is going to rely on IMAP and look a little like this:
  • Get a list of accounts
  • Provide the password for each account
  • Setup an initial sync of mailbox contents
  • Look for errors
  • On the day that you cut MX records, do another sync
  • On the day that you cut MX records, migrate local accounts
  • Do a final sync
  • Archive the spam account
  • Take the server offline
You can do this with less effort (e.g. users need to backup their mailboxes, do the sync once, etc), but in my experience the above process has produced the best result for the consumers of mail services and for customers of various types of consultancies. The technical portion of this is pretty straight forward if you follow these steps. The part I like the least is the fact that whosoever has access to those passwords has access to mailboxes, and your actions during that time are very much open to interpretation.

Let’s start by looking at the domains running on the mail server. We’ll do this with serveradmin, by looking at the settings of the mail:postfix:domains:_array_index:

sudo /Applications/Server.app/Contents/ServerRoot/usr/sbin/serveradmin settings mail:postfix:domains:_array_index:

The return will list all of the domains running on the server:

mail:postfix:domains:_array_index:0:name = "krypted.com"

mail:postfix:domains:_array_index:1:name = "kryptedadmin.com"

The primary domain, or the one in _array_index:0 should map to the mydomain variable in /Library/Server/Mail/Config/postfix/main.cf. All of the users will be stored in /Library/Server/Mail/Config/postfix/virtual_users. To see them, simply cat that file:

cat /Library/Server/Mail/Config/postfix/virtual_users

Which would return a line similar to this one for each email account:

charles.edge@krypted.com charles.edge

To just see a list of email address, you could run:

sudo cat /Library/Server/Mail/Config/postfix/virtual_users | grep -E -o "\b[a-zA-Z0-9.-]+@[a-zA-Z0-9.-]+\.[a-zA-Z0-9.-]+\b"

Now that you have a list of email address, you can easily put them into a file that will sync mailboxes. There are a number of tools you could use to migrate actual mail. These include:
Now, let’s look at using imapsync to actually sync a mailbox. In the most basic form, you could just do:

imapsync --host1 oldmail.krypted.com --user1 charles.edge --password1 mypassword --host2 newmail.krypted.com --user2 charles.edge --password2 mynewpassword

For a small set of users you could easily just paste this command into a .sh file, and run it then run it again the night of the sync, and then run a cleanup a couple of days later in case there were any stragglers. This isn’t going to work for everyone. A lot of people will use custom settings in mail apps. If necessary, you can also configure ports for both servers with –port1 and –port2. You can also configure SSL, synchrinization options, regular expression conversions on objects during the migration, include and exclude items with mail folders, move passwords into a file, etc. Before doing the sync, I’d recommend syncing a test mailbox and reading the entire manpage at https://github.com/imapsync/imapsync.

Changing MX and getting mail to actually flow to the new servers is just a matter of making sure there’s an A Record for the new mail server and putting the MX to that. I recommend setting the TTL of your dns records for mail servers as low as your DNS server or registrar will allow until the migration process is complete. The reason for this is that you want to keep the time frame that mail could flow to both servers at a minimum. The final sync is because DNS changes aren’t instant. Some DNS servers get a lot of traffic and so don’t respect the TTL for a given record. Therefore, that final sync pulls everything that might have accidentally been flowing into your old server into your new server. 

Next, you’ll need to change the host name of the mail server in mail clients and hopefully have users reset their passwords so you don’t have access to their mail any longer. For this, I recommend pushing a profile (e.g. using an MDM or command line equivalent). 

I have seen a number of environments (and helped in some cases) get really crafty. They might present a user with a forced “change password” dialog and then have that stored in a file that admins can’t access. It’s in clear text and there’s always risk. But this allows for non repudiation. It also means that when you send a profile to a device you can have the new account show up and work without the user having to enter a password. Every time users have to touch something, there’s the chance it will get mistyped (I typo things all the time) and there’s a chance that they’ll be confused and call you, so the larger the user base you’re migrating, the more logic you’ll hopefully be able to apply to this process to help keep your phone from ringing. I’ve also seen environments where admins had users type in the password, monitor the sync, and then proceed using client-side scripts. This has always been fraught with peril, but offers an added sense of privacy. 

Don’t forget to grab the mailbox. Seems like this is the main reason I’ve had to revive dead servers. Something got put there and someone needs it… Migrating that mailbox the same as you would any other is a good idea, just-in-case. If you don’t know your quarantine address, run the following to find it:

sudo serveradmin settings mail:postfix:spam_quarantine

Once you’re sure that no mail is flowing to the old server (72 hours is usually a good time frame), you can pull the old server offline. I recommend keeping the server or a clone of the server forever. I’ve needed to revive them here and there due to a variety of reasons that have nothing to do with data integrity of what was migrated. You never know. And if you’re a consultant, there’s no easier way to get fired than to go mucking about with access to mail without a lot of communication in advance. 

Overall, this process can be pretty seamless to your users. But it requires more labor on your side. To keep costs and effort down for you, you could type up a document that steps people through things, but I prefer people at work liking me, so wouldn’t do that personally. Good luck and please comment here if you have further tools or workflows that you prefer!

February 15th, 2018

Posted In: Mac OS X Server

Tags: , , ,

Mail is one of the hardest services to manage. Actually, mail is pretty simple in and of itself: there’s protocols people use to access their mail (such as IMAP and POP), protocols used to communicate between mail servers and send mail (SMTP, SMTPS) and then there’s a database of mail and user information. In macOS Server 5.4 for High Sierra, all of these are represented by a single ON button, so it really couldn’t be easier, once you can just enter email addresses into the Users section.

But then there’s the ecoysystem and the evil spammers. They’re totally the worst. Like ever. As the former systems administrator of a large number of mail servers, I firmly believe that there is a special kind of hell where only deep fried spam is served at every meal for spammers. Here, the evil spammers must also read every piece of spam ever sent for eternity. By the end (aka Ragnarok), they should plenty of chemically induced stamina, enough pills of other types to not be able to use that stamina, plenty of princes looking to donate large sums of money if only they can be helped out of their country (which should cost about $100,000 compared to a $5,000,000 payout, not a bad ROI, so DUH?!?!?), have their conflicting stamina situation at the top of the search engines and of course, have lost all of the money made from their princes due to getting their credit card hijacked by about 9,000 phishing scams. All in all, a special kind of hell…

But back to the point of the article, setting up mail. The things that mail administrators need to focus on to keep that mail server flowing mail to and from everyone else in the world:
  • Static IP address. The WAN (and LAN probably) address should be static.
  • Port Forwards. Port forwards need to be configured on the gateway for the SMTP port at a minimum and more than likely other ports used to access mail on client devices (25, 143, etc)
  • DNS records. An MX record and some kind of mail.domain.com type of record should definitely be configured for the DNS servers that are authoritative for the domain. There should also be reverse records for the address of the server, usually created by the Internet Services Provider, or ISP, that match that record.
  • Check the RBLs. If you have a new IP address you’ll be putting a DNS server on, check all the major Realtime BlackLists to make sure that some evil spammer hasn’t squatted on the IP before you got to it. This is true whether you’re in a colo, hosted on an IP you own or moving into space formerly occupied by a very standup company. A lot of IP addresses are blocked, as are blocks of IPs, so before moving mail to an IP, check it.
  • Mail filtration (message hygiene). OS X Server has a number of mail filters built in, including clam for viruses, the ability to leverage RBLs, block specific addresses and of course RBL checking. However, this is often not enough. Third party services such as MXLogic help to keep mail from coming into your network. You also end up with an external IP to send mail that can cache mail in the event the server is down and keep mail off your network in the event that it’s spam.
  • Backup. I am firmly of the belief that I’d rather not have data than not have that data backed up…
Once all of that is taken care of (I’ll add more as I think about it) then it’s time to enable the mail service in the Server app running on Yosemite. Actually, first let’s setup our SSL certificates. To do so, open the Server app and click on Certificates in the SERVER section of the sidebar. Here, use the “Secure services using” drop-down list and click on Custom… for each protocol to select the appropriate certificate to be used for the service.


Click OK when they’re all configure. Now let’s enable the mail service (or outsource mail). To do so, open the Server app and click on Mail in the SERVICES list in the sidebar.

 
At the configuration screen is a sparse number of settings:
  • Status: Indicates if the server is running.
  • Edit Permissions: Limits the IP addresses capable of connecting to the server.
  • Domains: Configures all of the domains the mail server will listen for mail for. Each account on the server has a short name and each domain name will be available for each short name. For example, an account with a shortname of charles will be available for email addresses of charles@pretendco.com and charles@krypted.com per the Domain Name listing below.
  • Authentication: Click Edit for a list of sources that accounts can authenticate against (e.g. Active Directory, Open Directory, Custom, Local, etc) and in some cases the specific password algorithms used for mail.
  • Push Notifications: If Push is configured previously there’s no need to use this option. Otherwise, use your institutional APNS account to configure Push Notifications.
  • Mail Relay: Provide a server that all mail will get routed through from the server. For example, this might be an account with your Internet Services Provider (ISP), an account on an appliance that you own (such as a Barracuda) or with an external filtering service (such as MXLogic).
  • Mailbox size: Configure the total amount of mail a user can have in the mail store, in Megabytes.
  • Filtering: Configure antivirus, spam assassin and junk mail filters. The “Enable virus filtering” checkbox enables clam. The “Enable blacklist filtering” checks the RBL (or RBLs) of your choice to check whether a given server is a “known” spammer and the “Enable junk mail filtering” option enables spam assassin on the host, configuring it to block based on a score as selected using the slider.
Once you’ve configured the settings for the Mail service, click on the ON slider to enable the service. At this point, you should be able to telnet into port 25 of the host to verify that SMTP is listening, preferably from another mail server:

telnet mail.krypted.com 25

You can also check that the mail services are running using the serveradmin command along with the fullstatus option for the mail service:

sudo serveradmin fullstatus mail

Which returns with some pretty verbose information about the service, including state, connections, running protocols and the rest of the following:

mail:startedTime = "" mail:setStateVersion = 1 mail:state = "STOPPED" mail:protocolsArray:_array_index:0:status = "ON" mail:protocolsArray:_array_index:0:kind = "INCOMING" mail:protocolsArray:_array_index:0:protocol = "IMAP" mail:protocolsArray:_array_index:0:state = "STOPPED" mail:protocolsArray:_array_index:0:service = "MailAccess" mail:protocolsArray:_array_index:0:error = "" mail:protocolsArray:_array_index:1:status = "ON" mail:protocolsArray:_array_index:1:kind = "INCOMING" mail:protocolsArray:_array_index:1:protocol = "POP3" mail:protocolsArray:_array_index:1:state = "STOPPED" mail:protocolsArray:_array_index:1:service = "MailAccess" mail:protocolsArray:_array_index:1:error = "" mail:protocolsArray:_array_index:2:status = "ON" mail:protocolsArray:_array_index:2:kind = "INCOMING" mail:protocolsArray:_array_index:2:protocol = "SMTP" mail:protocolsArray:_array_index:2:state = "STOPPED" mail:protocolsArray:_array_index:2:service = "MailTransferAgent" mail:protocolsArray:_array_index:2:error = "" mail:protocolsArray:_array_index:3:status = "ON" mail:protocolsArray:_array_index:3:kind = "OUTGOING" mail:protocolsArray:_array_index:3:protocol = "SMTP" mail:protocolsArray:_array_index:3:state = "STOPPED" mail:protocolsArray:_array_index:3:service = "MailTransferAgent" mail:protocolsArray:_array_index:3:error = "" mail:protocolsArray:_array_index:4:status = "OFF" mail:protocolsArray:_array_index:4:kind = "INCOMING" mail:protocolsArray:_array_index:4:protocol = "" mail:protocolsArray:_array_index:4:state = "STOPPED" mail:protocolsArray:_array_index:4:service = "ListServer" mail:protocolsArray:_array_index:4:error = "" mail:protocolsArray:_array_index:5:status = "ON" mail:protocolsArray:_array_index:5:kind = "INCOMING" mail:protocolsArray:_array_index:5:protocol = "" mail:protocolsArray:_array_index:5:state = "STOPPED" mail:protocolsArray:_array_index:5:service = "JunkMailFilter" mail:protocolsArray:_array_index:5:error = "" mail:protocolsArray:_array_index:6:status = "ON" mail:protocolsArray:_array_index:6:kind = "INCOMING" mail:protocolsArray:_array_index:6:protocol = "" mail:protocolsArray:_array_index:6:state = "STOPPED" mail:protocolsArray:_array_index:6:service = "VirusScanner" mail:protocolsArray:_array_index:6:error = "" mail:protocolsArray:_array_index:7:status = "ON" mail:protocolsArray:_array_index:7:kind = "INCOMING" mail:protocolsArray:_array_index:7:protocol = "" mail:protocolsArray:_array_index:7:state = "STOPPED" mail:protocolsArray:_array_index:7:service = "VirusDatabaseUpdater" mail:protocolsArray:_array_index:7:error = "" mail:logPaths:Server Error Log = "/Library/Logs/Mail/mail-err.log" mail:logPaths:IMAP Log = "/Library/Logs/Mail/mail-info.log" mail:logPaths:Server Log = "/Library/Logs/Mail/mail-info.log" mail:logPaths:POP Log = "/Library/Logs/Mail/mail-info.log" mail:logPaths:SMTP Log = "/var/log/mail.log" mail:logPaths:List Server Log = "/Library/Logs/Mail/listserver.log" mail:logPaths:Migration Log = "/Library/Logs/MailMigration.log" mail:logPaths:Virus Log = "/Library/Logs/Mail/clamav.log" mail:logPaths:Amavisd Log = "/Library/Logs/Mail/amavis.log" mail:logPaths:Virus DB Log = "/Library/Logs/Mail/freshclam.log" mail:imapStartedTime = "" mail:postfixStartedTime = "" mail:servicePortsRestrictionInfo = _empty_array mail:servicePortsAreRestricted = "NO" mail:connectionCount = 0 mail:readWriteSettingsVersion = 1 mail:serviceStatus = "DISABLED" To stop the service:

sudo serveradmin stop mail

And to start it back up:

sudo serveradmin start mail

To configure some of the settings no longer in the GUI from previous versions, let’s look at the full list of options:

sudo serveradmin settings mail

One that is commonly changed is the subject line added to messages that are marked as spam by spam assassin. This is stored in mail:postfix:spam_subject_tag, so changing would be:

sudo serveradmin settings mail:postfix:spam_subject_tag = "***DIEEVILSPAMMERSDIE*** "

A number of admins also choose to disable greylisting, done using the mail:postfix:greylist_disable option:

sudo serveradmin settings mail:postfix:greylist_disable = no

To configure an email address for quarantined mail to go, use mail:postfix:virus_quarantine:

sudo serveradmin settings mail:postfix:virus_quarantine = "diespammersdie@krypted.com"

The administrator, by default, doesn’t get an email when an email containing a file infected with a virus is sent through the server. To enable this option:

sudo serveradmin settings mail:postfix:virus_notify_admin = yes

I also find a lot of Mac environments want to accept email of pretty much any size. By default, message size limits are enabled. To disable:

sudo serveradmin settings mail:postfix:message_size_limit_enabled = yes

Or even better, just set new limit:

sudo serveradmin settings mail:postfix:message_size_limit = 10485760

And to configure the percentage of someone’s quota that kicks an alert (soft quota):

sudo serveradmin settings mail:imap:quotawarn = 75

Additionally, the following arrays are pretty helpful, which used to have GUI options:
  • mail:postfix:mynetworks:_array_index:0 = “127.0.0.0/8″ – Add entries to this one to add “local” clients
  • mail:postfix:host_whitelist = _empty_array – Add whitelisted hosts
  • mail:postfix:blacklist_from = _empty_array – Add blacklisted hosts
  • mail:postfix:black_hole_domains:_array_index:0 = “zen.spamhaus.org” – Add additional RBL Servers
The client side of the mail service is straight forward enough. If you are wondering where in this article we discuss using webmail, er, that’s not installed by default any longer. But the open source project previously used, roundcube, is still available for download and easily installed (the pre-reqs are all there, already). Check out the roundcube wiki installation page here for more info on that. Also, mail groups. I hope to have a post about that soon enough. Unless, of course, I get sidetracked with having a life. Which is arguably not very likely…

September 26th, 2017

Posted In: Mac OS X Server

Tags: , , , , , , , , , ,

Mail is one of the hardest services to manage. Actually, mail is pretty simple in and of itself: there’s protocols people use to access their mail (such as IMAP and POP), protocols used to communicate between mail servers and send mail (SMTP, SMTPS) and then there’s a database of mail and user information. In OS X Server 5 for El Capitan and Yosemite, all of these are represented by a single ON button, so it really couldn’t be easier. But then there’s the ecoysystem and the evil spammers. As a systems administrator of a large number of mail servers, I firmly believe that there is a special kind of hell where only spam is served at every meal for spammers. Here, the evil spammers must also read every piece of spam ever sent for eternity. By the end (aka Ragnarok), they should have the chemically induced stamina of a 16 year old with the latest Sports Illustrated Swimsuit issue, enough pills of other types to not be able to use that stamina, plenty of African princes looking to donate large sums of money if only they can be helped out of their country (which should cost about 100,000 compared to a 5,000,000 payout, not a bad ROI, right?!?!?), have their conflicting stamina situation at the top of the search engines and of course, have lost all of the money made from their African princes due to getting their credit card hijacked by about 9,000 phishing scams. All in all, a special kind of hell…  But back to the point of the article, setting up mail. The things that mail administrators need to focus on to keep that mail server flowing mail to and from everyone else in the world:
  • Static IP address. The WAN (and LAN probably) address should be static.
  • Port Forwards. Port forwards need to be configured on the gateway for the SMTP port at a minimum and more than likely other ports used to access mail on client devices (25, 143, etc)
  • DNS records. An MX record and some kind of mail.domain.com type of record should definitely be configured for the DNS servers that are authoritative for the domain. There should also be reverse records for the address of the server, usually created by the Internet Services Provider, or ISP, that match that record.
  • Check the RBLs. If you have a new IP address you’ll be putting a DNS server on, check all the major Realtime BlackLists to make sure that some evil spammer hasn’t squatted on the IP before you got to it. This is true whether you’re in a colo, hosted on an IP you own or moving into space formerly occupied by a very standup company. A lot of IP addresses are blocked, as are blocks of IPs, so before moving mail to an IP, check it.
  • Mail filtration (message hygiene). OS X Server has a number of mail filters built in, including clam for viruses, the ability to leverage RBLs, block specific addresses and of course RBL checking. However, this is often not enough. Third party services such as MXLogic help to keep mail from coming into your network. You also end up with an external IP to send mail that can cache mail in the event the server is down and keep mail off your network in the event that it’s spam.
  • Backup. I am firmly of the belief that I’d rather not have data than not have that data backed up…
Once all of that is taken care of (I’ll add more as I think about it) then it’s time to enable the mail service in the Server app running on Yosemite. Actually, first let’s setup our SSL certificates. To do so, open the Server app and click on Certificates in the SERVER section of the sidebar. Here, use the “Secure services using” drop-down list and click on Custom… for each protocol to select the appropriate certificate to be used for the service. Screen Shot 2015-09-22 at 11.16.20 PM Click OK when they’re all configure. Now let’s enable the mail service (or outsource mail). To do so, open the Server app and click on Mail in the SERVICES list in the sidebar. Mail2 At the configuration screen is a sparse number of settings:
  • Domains: Configures all of the domains the mail server will listen for mail for. Each account on the server has a short name and each domain name will be available for each short name. For example, an account with a shortname of charles will be available for email addresses of charles@pretendco.com and charles@krypted.com per the Domain Name listing below.Screen Shot 2015-09-22 at 11.17.27 PM
  • Authentication: Click Edit for a list of sources that accounts can authenticate against (e.g. Active Directory, Open Directory, Custom, Local, etc) and in some cases the specific password algorithms used for mail.Screen Shot 2015-09-22 at 11.18.12 PM
  • Push Notifications: If Push is configured previously there’s no need to use this option. Otherwise, use your institutional APNS account to configure Push Notifications.Screen Shot 2015-09-22 at 11.18.44 PM
  • Relay outgoing mail through ISP: Provide a server that all mail will get routed through from the server. For example, this might be an account with your Internet Services Provider (ISP), an account on an appliance that you own (such as a Barracuda) or with an external filtering service (such as MXLogic).Screen Shot 2015-09-22 at 11.19.42 PM
  • Limit mail to: Configure the total amount of mail a user can have in the mail store, in Megabytes.
  • Edit Filtering Settings: Configure antivirus, spam assassin and junk mail filters. The “Enable virus filtering” checkbox enables clam. The “Enable blacklist filtering” checks the RBL (or RBLs) of your choice to check whether a given server is a “known” spammer and the “Enable junk mail filtering” option enables spam assassin on the host, configuring it to block based on a score as selected using the slider.
Once you’ve configured the settings for the Mail service, click on the ON slider to enable the service. At this point, you should be able to telnet into port 25 of the host to verify that SMTP is listening, preferably from another mail server: telnet mail.krypted.com 25 You can also check that the mail services are running using the serveradmin command along with the fullstatus option for the mail service: sudo serveradmin fullstatus mail Which returns with some pretty verbose information about the service, including state, connections, running protocols and the rest of the following: mail:startedTime = ""
mail:setStateVersion = 1
mail:state = "STOPPED"
mail:protocolsArray:_array_index:0:status = "ON"
mail:protocolsArray:_array_index:0:kind = "INCOMING"
mail:protocolsArray:_array_index:0:protocol = "IMAP"
mail:protocolsArray:_array_index:0:state = "STOPPED"
mail:protocolsArray:_array_index:0:service = "MailAccess"
mail:protocolsArray:_array_index:0:error = ""
mail:protocolsArray:_array_index:1:status = "ON"
mail:protocolsArray:_array_index:1:kind = "INCOMING"
mail:protocolsArray:_array_index:1:protocol = "POP3"
mail:protocolsArray:_array_index:1:state = "STOPPED"
mail:protocolsArray:_array_index:1:service = "MailAccess"
mail:protocolsArray:_array_index:1:error = ""
mail:protocolsArray:_array_index:2:status = "ON"
mail:protocolsArray:_array_index:2:kind = "INCOMING"
mail:protocolsArray:_array_index:2:protocol = "SMTP"
mail:protocolsArray:_array_index:2:state = "STOPPED"
mail:protocolsArray:_array_index:2:service = "MailTransferAgent"
mail:protocolsArray:_array_index:2:error = ""
mail:protocolsArray:_array_index:3:status = "ON"
mail:protocolsArray:_array_index:3:kind = "OUTGOING"
mail:protocolsArray:_array_index:3:protocol = "SMTP"
mail:protocolsArray:_array_index:3:state = "STOPPED"
mail:protocolsArray:_array_index:3:service = "MailTransferAgent"
mail:protocolsArray:_array_index:3:error = ""
mail:protocolsArray:_array_index:4:status = "OFF"
mail:protocolsArray:_array_index:4:kind = "INCOMING"
mail:protocolsArray:_array_index:4:protocol = ""
mail:protocolsArray:_array_index:4:state = "STOPPED"
mail:protocolsArray:_array_index:4:service = "ListServer"
mail:protocolsArray:_array_index:4:error = ""
mail:protocolsArray:_array_index:5:status = "ON"
mail:protocolsArray:_array_index:5:kind = "INCOMING"
mail:protocolsArray:_array_index:5:protocol = ""
mail:protocolsArray:_array_index:5:state = "STOPPED"
mail:protocolsArray:_array_index:5:service = "JunkMailFilter"
mail:protocolsArray:_array_index:5:error = ""
mail:protocolsArray:_array_index:6:status = "ON"
mail:protocolsArray:_array_index:6:kind = "INCOMING"
mail:protocolsArray:_array_index:6:protocol = ""
mail:protocolsArray:_array_index:6:state = "STOPPED"
mail:protocolsArray:_array_index:6:service = "VirusScanner"
mail:protocolsArray:_array_index:6:error = ""
mail:protocolsArray:_array_index:7:status = "ON"
mail:protocolsArray:_array_index:7:kind = "INCOMING"
mail:protocolsArray:_array_index:7:protocol = ""
mail:protocolsArray:_array_index:7:state = "STOPPED"
mail:protocolsArray:_array_index:7:service = "VirusDatabaseUpdater"
mail:protocolsArray:_array_index:7:error = ""
mail:logPaths:Server Error Log = "/Library/Logs/Mail/mail-err.log"
mail:logPaths:IMAP Log = "/Library/Logs/Mail/mail-info.log"
mail:logPaths:Server Log = "/Library/Logs/Mail/mail-info.log"
mail:logPaths:POP Log = "/Library/Logs/Mail/mail-info.log"
mail:logPaths:SMTP Log = "/var/log/mail.log"
mail:logPaths:List Server Log = "/Library/Logs/Mail/listserver.log"
mail:logPaths:Migration Log = "/Library/Logs/MailMigration.log"
mail:logPaths:Virus Log = "/Library/Logs/Mail/clamav.log"
mail:logPaths:Amavisd Log = "/Library/Logs/Mail/amavis.log"
mail:logPaths:Virus DB Log = "/Library/Logs/Mail/freshclam.log"
mail:imapStartedTime = ""
mail:postfixStartedTime = ""
mail:servicePortsRestrictionInfo = _empty_array
mail:servicePortsAreRestricted = "NO"
mail:connectionCount = 0
mail:readWriteSettingsVersion = 1
mail:serviceStatus = "DISABLED" To stop the service: sudo serveradmin stop mail And to start it back up: sudo serveradmin start mail To configure some of the settings no longer in the GUI from previous versions, let’s look at the full list of options: sudo serveradmin settings mail One that is commonly changed is the subject line added to messages that are marked as spam by spam assassin. This is stored in mail:postfix:spam_subject_tag, so changing would be: sudo serveradmin settings mail:postfix:spam_subject_tag = "***DIEEVILSPAMMERSDIE*** " A number of admins also choose to disable greylisting, done using the mail:postfix:greylist_disable option: sudo serveradmin settings mail:postfix:greylist_disable = no To configure an email address for quarantined mail to go, use mail:postfix:virus_quarantine: sudo serveradmin settings mail:postfix:virus_quarantine = "diespammersdie@krypted.com" The administrator, by default, doesn’t get an email when an email containing a file infected with a virus is sent through the server. To enable this option: sudo serveradmin settings mail:postfix:virus_notify_admin = yes I also find a lot of Mac environments want to accept email of pretty much any size. By default, message size limits are enabled. To disable: sudo serveradmin settings mail:postfix:message_size_limit_enabled = yes Or even better, just set new limit: sudo serveradmin settings mail:postfix:message_size_limit = 10485760 And to configure the percentage of someone’s quota that kicks an alert (soft quota): sudo serveradmin settings mail:imap:quotawarn = 75 Additionally, the following arrays are pretty helpful, which used to have GUI options:
  • mail:postfix:mynetworks:_array_index:0 = “127.0.0.0/8″ – Add entries to this one to add “local” clients
  • mail:postfix:host_whitelist = _empty_array – Add whitelisted hosts
  • mail:postfix:blacklist_from = _empty_array – Add blacklisted hosts
  • mail:postfix:black_hole_domains:_array_index:0 = “zen.spamhaus.org” – Add additional RBL Servers
The client side of the mail service is straight forward enough. If you are wondering where in this article we discuss using webmail, er, that’s not installed by default any longer. But the open source project previously used, roundcube, is still available for download and easily installed (the pre-reqs are all there, already). Check out the roundcube wiki installation page here for more info on that. Also, mail groups. I hope to have a post about that soon enough. Unless, of course, I get sidetracked with having a life. Which is arguably not very likely…

September 24th, 2015

Posted In: Mac OS X Server

Tags: , , , , , , , , , , , , ,

Mail is one of the hardest services to manage. Actually, mail is pretty simple in and of itself: there’s protocols people use to access their mail (such as IMAP and POP), protocols used to communicate between mail servers and send mail (SMTP, SMTPS) and then there’s a database of mail and user information. In Mavericks Server, all of these are represented by a single ON button, so it really couldn’t be easier. But then there’s the ecoysystem and the evil spammers. As a systems administrator of a large number of mail servers, I firmly believe that there is a special kind of hell where only spam is served at every meal for spammers. Here, the evil spammers must also read every piece of spam ever sent for eternity. By the end (aka Ragnarok), they should have the chemically induced stamina of a 16 year old with the latest Sports Illustrated Swimsuit issue, enough pills of other types to not be able to use that stamina, plenty of African princes looking to donate large sums of money if only they can be helped out of their country (which should cost about 100,000 compared to a 5,000,000 payout, not a bad ROI, right?!?!?), have their conflicting stamina situation at the top of the search engines and of course, have lost all of the money made from their African princes due to getting their credit card hijacked by about 9,000 phishing scams. All in all, a special kind of hell…  But back to the point of the article, setting up mail. The things that mail administrators need to focus on to keep that mail server flowing mail to and from everyone else in the world:
  • Static IP address. The WAN (and LAN probably) address should be static.
  • Port Forwards. Port forwards need to be configured on the gateway for the SMTP port at a minimum and more than likely other ports used to access mail on client devices (25, 143, etc)
  • DNS records. An MX record and some kind of mail.domain.com type of record should definitely be configured for the DNS servers that are authoritative for the domain. There should also be reverse records for the address of the server, usually created by the Internet Services Provider, or ISP, that match that record.
  • Check the RBLs. If you have a new IP address you’ll be putting a DNS server on, check all the major Realtime BlackLists to make sure that some evil spammer hasn’t squatted on the IP before you got to it. This is true whether you’re in a colo, hosted on an IP you own or moving into space formerly occupied by a very standup company. A lot of IP addresses are blocked, as are blocks of IPs, so before moving mail to an IP, check it.
  • Mail filtration (message hygiene). OS X Server has a number of mail filters built in, including clam for viruses, the ability to leverage RBLs, block specific addresses and of course RBL checking. However, this is often not enough. Third party services such as MXLogic help to keep mail from coming into your network. You also end up with an external IP to send mail that can cache mail in the event the server is down and keep mail off your network in the event that it’s spam.
  • Backup. I am firmly of the belief that I’d rather not have data than not have that data backed up…
Once all of that is taken care of (I’ll add more as I think about it) then it’s time to enable the mail service in the Server app running on Yosemite. Actually, first let’s setup our SSL certificates. To do so, open the Server app and click on Certificates in the SERVER section of the sidebar. Here, use the “Secure services using” drop-down list and click on Custom… for each protocol to select the appropriate certificate to be used for the service. Mail1 Click OK when they’re all configure. Now let’s enable the mail service (or outsource mail). To do so, open the Server app and click on Mail in the SERVICES list in the sidebar. Mail2 At the configuration screen is a sparse number of settings:
  • Provide mail for: Configures all of the domains the mail server will listen for mail for. Each account on the server has a short name and each domain name will be available for each short name. For example, an account with a shortname of charles will be available for email addresses of charles@pretendco.com and charles@krypted.com per the Domain Name listing below.Mail3
  • Authentication: Click Edit for a list of sources that accounts can authenticate against (e.g. Active Directory, Open Directory, Custom, Local, etc) and in some cases the specific password algorithms used for mail.Mail4
  • Push Notifications: If Push is configured previously there’s no need to use this option. Otherwise, use your institutional APNS account to configure Push Notifications.Mail5
  • Relay outgoing mail through ISP: Provide a server that all mail will get routed through from the server. For example, this might be an account with your Internet Services Provider (ISP), an account on an appliance that you own (such as a Barracuda) or with an external filtering service (such as MXLogic).Mail6
  • Limit mail to: Configure the total amount of mail a user can have in the mail store, in Megabytes.
  • Edit Filtering Settings: Configure antivirus, spam assassin and junk mail filters. The “Enable virus filtering” checkbox enables clam. The “Enable blacklist filtering” checks the RBL (or RBLs) of your choice to check whether a given server is a “known” spammer and the “Enable junk mail filtering” option enables spam assassin on the host, configuring it to block based on a score as selected using the slider.
Once you’ve configured the settings for the Mail service, click on the ON slider to enable the service. At this point, you should be able to telnet into port 25 of the host to verify that SMTP is listening, preferably from another mail server: telnet mail.krypted.com 25 You can also check that the mail services are running using the serveradmin command along with the fullstatus option for the mail service: sudo serveradmin fullstatus mail Which returns with some pretty verbose information about the service, including state, connections, running protocols and the rest of the following: mail:startedTime = ""
mail:setStateVersion = 1
mail:state = "STOPPED"
mail:protocolsArray:_array_index:0:status = "ON"
mail:protocolsArray:_array_index:0:kind = "INCOMING"
mail:protocolsArray:_array_index:0:protocol = "IMAP"
mail:protocolsArray:_array_index:0:state = "STOPPED"
mail:protocolsArray:_array_index:0:service = "MailAccess"
mail:protocolsArray:_array_index:0:error = ""
mail:protocolsArray:_array_index:1:status = "ON"
mail:protocolsArray:_array_index:1:kind = "INCOMING"
mail:protocolsArray:_array_index:1:protocol = "POP3"
mail:protocolsArray:_array_index:1:state = "STOPPED"
mail:protocolsArray:_array_index:1:service = "MailAccess"
mail:protocolsArray:_array_index:1:error = ""
mail:protocolsArray:_array_index:2:status = "ON"
mail:protocolsArray:_array_index:2:kind = "INCOMING"
mail:protocolsArray:_array_index:2:protocol = "SMTP"
mail:protocolsArray:_array_index:2:state = "STOPPED"
mail:protocolsArray:_array_index:2:service = "MailTransferAgent"
mail:protocolsArray:_array_index:2:error = ""
mail:protocolsArray:_array_index:3:status = "ON"
mail:protocolsArray:_array_index:3:kind = "OUTGOING"
mail:protocolsArray:_array_index:3:protocol = "SMTP"
mail:protocolsArray:_array_index:3:state = "STOPPED"
mail:protocolsArray:_array_index:3:service = "MailTransferAgent"
mail:protocolsArray:_array_index:3:error = ""
mail:protocolsArray:_array_index:4:status = "OFF"
mail:protocolsArray:_array_index:4:kind = "INCOMING"
mail:protocolsArray:_array_index:4:protocol = ""
mail:protocolsArray:_array_index:4:state = "STOPPED"
mail:protocolsArray:_array_index:4:service = "ListServer"
mail:protocolsArray:_array_index:4:error = ""
mail:protocolsArray:_array_index:5:status = "ON"
mail:protocolsArray:_array_index:5:kind = "INCOMING"
mail:protocolsArray:_array_index:5:protocol = ""
mail:protocolsArray:_array_index:5:state = "STOPPED"
mail:protocolsArray:_array_index:5:service = "JunkMailFilter"
mail:protocolsArray:_array_index:5:error = ""
mail:protocolsArray:_array_index:6:status = "ON"
mail:protocolsArray:_array_index:6:kind = "INCOMING"
mail:protocolsArray:_array_index:6:protocol = ""
mail:protocolsArray:_array_index:6:state = "STOPPED"
mail:protocolsArray:_array_index:6:service = "VirusScanner"
mail:protocolsArray:_array_index:6:error = ""
mail:protocolsArray:_array_index:7:status = "ON"
mail:protocolsArray:_array_index:7:kind = "INCOMING"
mail:protocolsArray:_array_index:7:protocol = ""
mail:protocolsArray:_array_index:7:state = "STOPPED"
mail:protocolsArray:_array_index:7:service = "VirusDatabaseUpdater"
mail:protocolsArray:_array_index:7:error = ""
mail:logPaths:Server Error Log = "/Library/Logs/Mail/mail-err.log"
mail:logPaths:IMAP Log = "/Library/Logs/Mail/mail-info.log"
mail:logPaths:Server Log = "/Library/Logs/Mail/mail-info.log"
mail:logPaths:POP Log = "/Library/Logs/Mail/mail-info.log"
mail:logPaths:SMTP Log = "/var/log/mail.log"
mail:logPaths:List Server Log = "/Library/Logs/Mail/listserver.log"
mail:logPaths:Migration Log = "/Library/Logs/MailMigration.log"
mail:logPaths:Virus Log = "/Library/Logs/Mail/clamav.log"
mail:logPaths:Amavisd Log = "/Library/Logs/Mail/amavis.log"
mail:logPaths:Virus DB Log = "/Library/Logs/Mail/freshclam.log"
mail:imapStartedTime = ""
mail:postfixStartedTime = ""
mail:servicePortsRestrictionInfo = _empty_array
mail:servicePortsAreRestricted = "NO"
mail:connectionCount = 0
mail:readWriteSettingsVersion = 1
mail:serviceStatus = "DISABLED" To stop the service: sudo serveradmin stop mail And to start it back up: sudo serveradmin start mail To configure some of the settings no longer in the GUI from previous versions, let’s look at the full list of options: sudo serveradmin settings mail One that is commonly changed is the subject line added to messages that are marked as spam by spam assassin. This is stored in mail:postfix:spam_subject_tag, so changing would be: sudo serveradmin settings mail:postfix:spam_subject_tag = "***DIEEVILSPAMMERSDIE*** " A number of admins also choose to disable greylisting, done using the mail:postfix:greylist_disable option: sudo serveradmin settings mail:postfix:greylist_disable = no To configure an email address for quarantined mail to go, use mail:postfix:virus_quarantine: sudo serveradmin settings mail:postfix:virus_quarantine = "diespammersdie@krypted.com" The administrator, by default, doesn’t get an email when an email containing a file infected with a virus is sent through the server. To enable this option: sudo serveradmin settings mail:postfix:virus_notify_admin = yes I also find a lot of Mac environments want to accept email of pretty much any size. By default, message size limits are enabled. To disable: sudo serveradmin settings mail:postfix:message_size_limit_enabled = yes Or even better, just set new limit: sudo serveradmin settings mail:postfix:message_size_limit = 10485760 And to configure the percentage of someone’s quota that kicks an alert (soft quota): sudo serveradmin settings mail:imap:quotawarn = 75 Additionally, the following arrays are pretty helpful, which used to have GUI options:
  • mail:postfix:mynetworks:_array_index:0 = “127.0.0.0/8″ – Add entries to this one to add “local” clients
  • mail:postfix:host_whitelist = _empty_array – Add whitelisted hosts
  • mail:postfix:blacklist_from = _empty_array – Add blacklisted hosts
  • mail:postfix:black_hole_domains:_array_index:0 = “zen.spamhaus.org” – Add additional RBL Servers
The client side of the mail service is straight forward enough. If you are wondering where in this article we discuss using webmail, er, that’s not installed by default any longer. But the open source project previously used, roundcube, is still available for download and easily installed (the pre-reqs are all there, already). Check out the roundcube wiki installation page here for more info on that. Also, mail groups. I hope to have a post about that soon enough. Unless, of course, I get sidetracked with having a life. Which is arguably not very likely…

October 17th, 2014

Posted In: Mac OS X, Mac OS X Server, Mac Security, Microsoft Exchange Server

Tags: , , , , , , , , , , , , , ,

Mail is one of the hardest services to manage. Actually, mail is pretty simple in and of itself: there’s protocols people use to access their mail (such as IMAP and POP), protocols used to communicate between mail servers and send mail (SMTP, SMTPS) and then there’s a database of mail and user information. In Mavericks Server, all of these are represented by a single ON button, so it really couldn’t be easier. But then there’s the ecoysystem and the evil spammers. As a systems administrator of a large number of mail servers, I firmly believe that there is a special kind of hell where only spam is served at every meal for spammers. Here, the evil spammers must also read every piece of spam ever sent for eternity. By the end (aka Ragnarok), they should have the chemically induced stamina of a 16 year old with the latest Sports Illustrated Swimsuit issue, enough pills of other types to not be able to use that stamina, plenty of African princes looking to donate large sums of money if only they can be helped out of their country (which should cost about 100,000 compared to a 5,000,000 payout, not a bad ROI, right?!?!?), have their conflicting stamina situation at the top of the search engines and of course, have lost all of the money made from their African princes due to getting their credit card hijacked by about 9,000 phishing scams. All in all, a special kind of hell…

But back to the point of the article, setting up mail. The things that mail administrators need to focus on to keep that mail server flowing mail to and from everyone else in the world:
  • Static IP address. The WAN (and LAN probably) address should be static.
  • Port Forwards. Port forwards need to be configured on the gateway for the SMTP port at a minimum and more than likely other ports used to access mail on client devices (25, 143, etc)
  • DNS records. An MX record and some kind of mail.domain.com type of record should definitely be configured for the DNS servers that are authoritative for the domain. There should also be reverse records for the address of the server, usually created by the Internet Services Provider, or ISP, that match that record.
  • Check the RBLs. If you have a new IP address you’ll be putting a DNS server on, check all the major Realtime BlackLists to make sure that some evil spammer hasn’t squatted on the IP before you got to it. This is true whether you’re in a colo, hosted on an IP you own or moving into space formerly occupied by a very standup company. A lot of IP addresses are blocked, as are blocks of IPs, so before moving mail to an IP, check it.
  • Mail filtration (message hygiene). OS X Server has a number of mail filters built in, including clam for viruses, the ability to leverage RBLs, block specific addresses and of course RBL checking. However, this is often not enough. Third party services such as MXLogic help to keep mail from coming into your network. You also end up with an external IP to send mail that can cache mail in the event the server is down and keep mail off your network in the event that it’s spam.
  • Backup. I am firmly of the belief that I’d rather not have data than not have that data backed up…
Once all of that is taken care of (I’ll add more as I think about it) then it’s time to enable the mail service in Server app 3. Actually, first let’s setup our SSL certificates. To do so, open the Server app and click on Certificates in the SERVER section of the sidebar. Here, use the “Secure services using” drop-down list and click on Custom… for each protocol to select the appropriate certificate to be used for the service. Screen Shot 2013-10-06 at 9.04.25 PM Click OK when they’re all configure. Now let’s enable the mail service (or outsource mail). To do so, open the Server app and click on Mail in the SERVICES list in the sidebar. Screen Shot 2013-10-06 at 9.05.02 PMAt the configuration screen is a sparse number of settings:
  • Provide mail for: Configures all of the domains the mail server will listen for mail for. Each account on the server has a short name and each domain name will be available for each short name. For example, an account with a shortname of charles will be available for email addresses of charles@pretendco.com and charles@krypted.com per the Domain Name listing below.Screen Shot 2013-10-06 at 9.05.45 PM
  • Authentication: Click Edit for a list of sources that accounts can authenticate against (e.g. Active Directory, Open Directory, Custom, Local, etc) and in some cases the specific password algorithms used for mail.Screen Shot 2013-10-06 at 9.06.17 PM
  • Push Notifications: If Push is configured previously there’s no need to use this option. Otherwise, use your institutional APNS account to configure Push Notifications.Screen Shot 2013-10-06 at 9.07.25 PM
  • Relay outgoing mail through ISP: Provide a server that all mail will get routed through from the server. For example, this might be an account with your Internet Services Provider (ISP), an account on an appliance that you own (such as a Barracuda) or with an external filtering service (such as MXLogic).Screen Shot 2013-10-06 at 9.07.57 PM
  • Limit mail to: Configure the total amount of mail a user can have in the mail store, in Megabytes.
  • Edit Filtering Settings: Configure antivirus, spam assassin and junk mail filters. The “Enable virus filtering” checkbox enables clam. The “Enable blacklist filtering” checks the RBL (or RBLs) of your choice to check whether a given server is a “known” spammer and the “Enable junk mail filtering” option enables spam assassin on the host, configuring it to block based on a score as selected using the slider.Screen Shot 2013-10-06 at 9.08.44 PM
Once you’ve configured the settings for the Mail service, click on the ON slider to enable the service. At this point, you should be able to telnet into port 25 of the host to verify that SMTP is listening, preferably from another mail server: telnet mail.krypted.com 25 You can also check that the mail services are running using the serveradmin command along with the fullstatus option for the mail service: sudo serveradmin fullstatus mail Which returns with some pretty verbose information about the service, including state, connections, running protocols and the rest of the following: mail:startedTime = "" mail:setStateVersion = 1 mail:state = "STOPPED" mail:protocolsArray:_array_index:0:status = "ON" mail:protocolsArray:_array_index:0:kind = "INCOMING" mail:protocolsArray:_array_index:0:protocol = "IMAP" mail:protocolsArray:_array_index:0:state = "STOPPED" mail:protocolsArray:_array_index:0:service = "MailAccess" mail:protocolsArray:_array_index:0:error = "" mail:protocolsArray:_array_index:1:status = "ON" mail:protocolsArray:_array_index:1:kind = "INCOMING" mail:protocolsArray:_array_index:1:protocol = "POP3" mail:protocolsArray:_array_index:1:state = "STOPPED" mail:protocolsArray:_array_index:1:service = "MailAccess" mail:protocolsArray:_array_index:1:error = "" mail:protocolsArray:_array_index:2:status = "ON" mail:protocolsArray:_array_index:2:kind = "INCOMING" mail:protocolsArray:_array_index:2:protocol = "SMTP" mail:protocolsArray:_array_index:2:state = "STOPPED" mail:protocolsArray:_array_index:2:service = "MailTransferAgent" mail:protocolsArray:_array_index:2:error = "" mail:protocolsArray:_array_index:3:status = "ON" mail:protocolsArray:_array_index:3:kind = "OUTGOING" mail:protocolsArray:_array_index:3:protocol = "SMTP" mail:protocolsArray:_array_index:3:state = "STOPPED" mail:protocolsArray:_array_index:3:service = "MailTransferAgent" mail:protocolsArray:_array_index:3:error = "" mail:protocolsArray:_array_index:4:status = "OFF" mail:protocolsArray:_array_index:4:kind = "INCOMING" mail:protocolsArray:_array_index:4:protocol = "" mail:protocolsArray:_array_index:4:state = "STOPPED" mail:protocolsArray:_array_index:4:service = "ListServer" mail:protocolsArray:_array_index:4:error = "" mail:protocolsArray:_array_index:5:status = "ON" mail:protocolsArray:_array_index:5:kind = "INCOMING" mail:protocolsArray:_array_index:5:protocol = "" mail:protocolsArray:_array_index:5:state = "STOPPED" mail:protocolsArray:_array_index:5:service = "JunkMailFilter" mail:protocolsArray:_array_index:5:error = "" mail:protocolsArray:_array_index:6:status = "ON" mail:protocolsArray:_array_index:6:kind = "INCOMING" mail:protocolsArray:_array_index:6:protocol = "" mail:protocolsArray:_array_index:6:state = "STOPPED" mail:protocolsArray:_array_index:6:service = "VirusScanner" mail:protocolsArray:_array_index:6:error = "" mail:protocolsArray:_array_index:7:status = "ON" mail:protocolsArray:_array_index:7:kind = "INCOMING" mail:protocolsArray:_array_index:7:protocol = "" mail:protocolsArray:_array_index:7:state = "STOPPED" mail:protocolsArray:_array_index:7:service = "VirusDatabaseUpdater" mail:protocolsArray:_array_index:7:error = "" mail:logPaths:Server Error Log = "/Library/Logs/Mail/mail-err.log" mail:logPaths:IMAP Log = "/Library/Logs/Mail/mail-info.log" mail:logPaths:Server Log = "/Library/Logs/Mail/mail-info.log" mail:logPaths:POP Log = "/Library/Logs/Mail/mail-info.log" mail:logPaths:SMTP Log = "/var/log/mail.log" mail:logPaths:List Server Log = "/Library/Logs/Mail/listserver.log" mail:logPaths:Migration Log = "/Library/Logs/MailMigration.log" mail:logPaths:Virus Log = "/Library/Logs/Mail/clamav.log" mail:logPaths:Amavisd Log = "/Library/Logs/Mail/amavis.log" mail:logPaths:Virus DB Log = "/Library/Logs/Mail/freshclam.log" mail:imapStartedTime = "" mail:postfixStartedTime = "" mail:servicePortsRestrictionInfo = _empty_array mail:servicePortsAreRestricted = "NO" mail:connectionCount = 0 mail:readWriteSettingsVersion = 1 mail:serviceStatus = "DISABLED" To stop the service: sudo serveradmin stop mail And to start it back up: sudo serveradmin start mail To configure some of the settings no longer in the GUI from previous versions, let’s look at the full list of options: sudo serveradmin settings mail One that is commonly changed is the subject line added to messages that are marked as spam by spam assassin. This is stored in mail:postfix:spam_subject_tag, so changing would be: sudo serveradmin settings mail:postfix:spam_subject_tag = "***DIEEVILSPAMMERSDIE*** " A number of admins also choose to disable greylisting, done using the mail:postfix:greylist_disable option: sudo serveradmin settings mail:postfix:greylist_disable = no To configure an email address for quarantined mail to go, use mail:postfix:virus_quarantine: sudo serveradmin settings mail:postfix:virus_quarantine = "diespammersdie@krypted.com" The administrator, by default, doesn’t get an email when an email containing a file infected with a virus is sent through the server. To enable this option: sudo serveradmin settings mail:postfix:virus_notify_admin = yes I also find a lot of Mac environments want to accept email of pretty much any size. By default, message size limits are enabled. To disable: sudo serveradmin settings mail:postfix:message_size_limit_enabled = yes Or even better, just set new limit: sudo serveradmin settings mail:postfix:message_size_limit = 10485760 And to configure the percentage of someone’s quota that kicks an alert (soft quota): sudo serveradmin settings mail:imap:quotawarn = 75 Additionally, the following arrays are pretty helpful, which used to have GUI options:
  • mail:postfix:mynetworks:_array_index:0 = “127.0.0.0/8” – Add entries to this one to add “local” clients
  • mail:postfix:host_whitelist = _empty_array – Add whitelisted hosts
  • mail:postfix:blacklist_from = _empty_array – Add blacklisted hosts
  • mail:postfix:black_hole_domains:_array_index:0 = “zen.spamhaus.org” – Add additional RBL Servers
The client side of the mail service is straight forward enough. If you are wondering where in this article we discuss using webmail, er, that’s not installed by default any longer. But the open source project previously used, roundcube, is still available for download and easily installed (the pre-reqs are all there, already). Check out the roundcube wiki installation page here for more info on that. Also, mail groups. I hope to have a post about that soon enough. Unless, of course, I get sidetracked with having a life. Which is arguably not very likely…

October 23rd, 2013

Posted In: Kerio, Mac OS X, Mac OS X Server

Tags: , , , , , , , , , , , , , , , ,

Mail is one of the hardest services to manage. Actually, mail is pretty simple in and of itself: there’s protocols people use to access their mail (such as IMAP and POP), protocols used to communicate between mail servers and send mail (SMTP, SMTPS)  and then there’s a database of mail and user information. In Mount Lion Server, all of these are represented by a single ON button, so it really couldn’t be easier. But then there’s the ecoysystem and the evil spammers. As a systems administrator of a large number of mail servers, I firmly believe that there is a special kind of hell where only spam is served at every meal for spammers. Here, the evil spammers must also read every piece of spam ever sent for eternity. By the end (aka Ragnarok), they should be fairly well hung, have chemically induced stamina of a 16 year old with the latest Sports Illustrated Swimsuit issue, enough pills of other types to not be able to use that stamina, plenty of African princes looking to donate large sums of money if only they can be helped out of their country (which should cost about 100,000 compared to a 5,000,000 payout, not a bad ROI, right?!?!?), have their conflicting stamina situation at the top of the search engines and of course, have lost all of the money made from their African princes due to getting their credit card hijacked by about 9,000 phishing scams. All in all, a special kind of hell…

But back to the point of the article, setting up mail… The things that mail administrators need to focus on to keep that mail server flowing mail to and from everyone else in the world:
  • Static IP address. The WAN (and LAN probably) address should be static.
  • Port Forwards. Port forwards need to be configured on the gateway for the SMTP port at a minimum and more than likely other ports used to access mail on client devices (25, 143, etc)
  • DNS records. An MX record and some kind of mail.domain.com type of record should definitely be configured for the DNS servers that are authoritative for the domain. There should also be reverse records for the address of the server, usually created by the Internet Services Provider, or ISP, that match that record.
  • Check the RBLs. If you have a new IP address you’ll be putting a DNS server on, check all the major Realtime BlackLists to make sure that some evil spammer hasn’t squatted on the IP before you got to it. This is true whether you’re in a colo, hosted on an IP you own or moving into space formerly occupied by a very standup company. A lot of IP addresses are blocked, as are blocks of IPs, so before moving mail to an IP, check it.
  • Mail filtration (message hygiene). OS X Server has a number of mail filters built in, including clam for viruses, the ability to leverage RBLs, block specific addresses and of course RBL checking. However, this is often not enough. Third party services such as MXLogic help to keep mail from coming into your network. You also end up with an external IP to send mail that can cache mail in the event the server is down and keep mail off your network in the event that it’s spam.
  • Backup. I am firmly of the belief that I’d rather not have data than not have that data backed up…
Once all of that is taken care of (I’ll add more as I think about it) then it’s time to enable the mail service. Actually, first let’s setup our SSL certificates. To do so, open the Server app and click on the name of the server in the HARDWARE section of the sidebar. Then click on the Settings tab and then the Edit button beside the SSL Certificate entry. Here, use the Certificate drop-down list for each protocol to select the appropriate certificate to be used for the service. Click OK when they’re all configure. Now let’s enable the mail service (or outsource mail). To do so, open the Server app and click on Mail in the SERVICES list in the sidebar. At the configuration screen is a sparse number of settings:
  • Provide mail for: Configures all of the domains the mail server will listen for mail for. Each account on the server has a short name and each domain name will be available for each short name. For example, an account with a shortname of charles will be available for email addresses of charles@pretendco.com and charles@krypted.com per the Domain Name listing below.
  • Authentication: Click Edit for a list of sources that accounts can authenticate against (e.g. Active Directory, Open Directory, Custom, Local, etc) and in some cases the specific password algorithms used for mail.
  • Relay outgoing mail through ISP: Provide a server that all mail will get routed through from the server. For example, this might be an account with your Internet Services Provider (ISP), an account on an appliance that you own (such as a Barracuda) or with an external filtering service (such as MXLogic).
  • Limit mail to: Configure the total amount of mail a user can have in the mail store, in Megabytes.
  • Edit Filtering Settings: Configure antivirus, spam assassin and junk mail filters. The “Enable virus filtering” checkbox enables clam. The “Enable blacklist filtering” checks the RBL (or RBLs) of your choice to check whether a given server is a “known” spammer and the “Enable junk mail filtering” option enables spam assassin on the host, configuring it to block based on a score as selected using the slider.
Once you’ve configured the settings for the Mail service, click on the ON slider to enable the service. At this point, you should be able to telnet into port 25 of the host to verify that SMTP is listening, preferably from another mail server: telnet mail.krypted.com 25 You can also check that the mail services are running using the serveradmin command along with the fullstatus option for the mail service: sudo serveradmin fullstatus mail Which returns with some pretty verbose information about the service, including state, connections, running protocols and the rest of the following: mail:setStateVersion = 1 mail:readWriteSettingsVersion = 1 mail:connectionCount = 0 mail:servicePortsRestrictionInfo = _empty_array mail:protocolsArray:_array_index:0:status = "ON" mail:protocolsArray:_array_index:0:kind = "INCOMING" mail:protocolsArray:_array_index:0:protocol = "IMAP" mail:protocolsArray:_array_index:0:state = "RUNNING" mail:protocolsArray:_array_index:0:error = "" mail:protocolsArray:_array_index:1:status = "ON" mail:protocolsArray:_array_index:1:kind = "INCOMING" mail:protocolsArray:_array_index:1:protocol = "POP3" mail:protocolsArray:_array_index:1:state = "RUNNING" mail:protocolsArray:_array_index:1:error = "" mail:protocolsArray:_array_index:2:status = "ON" mail:protocolsArray:_array_index:2:kind = "INCOMING" mail:protocolsArray:_array_index:2:protocol = "SMTP" mail:protocolsArray:_array_index:2:state = "RUNNING" mail:protocolsArray:_array_index:2:error = "" mail:protocolsArray:_array_index:3:status = "ON" mail:protocolsArray:_array_index:3:kind = "OUTGOING" mail:protocolsArray:_array_index:3:protocol = "SMTP" mail:protocolsArray:_array_index:3:state = "RUNNING" mail:protocolsArray:_array_index:3:error = "" mail:protocolsArray:_array_index:4:status = "ON" mail:protocolsArray:_array_index:4:kind = "INCOMING" mail:protocolsArray:_array_index:4:protocol = "Junk_mail_filter" mail:protocolsArray:_array_index:4:state = "STOPPED" mail:protocolsArray:_array_index:4:error = "" mail:protocolsArray:_array_index:5:status = "ON" mail:protocolsArray:_array_index:5:kind = "INCOMING" mail:protocolsArray:_array_index:5:protocol = "Virus_scanner" mail:protocolsArray:_array_index:5:state = "STOPPED" mail:protocolsArray:_array_index:5:error = "" mail:startedTime = "2012-07-30 18:14:26 +0000" mail:logPaths:IMAP Log = "/Library/Logs/Mail/mailaccess.log" mail:logPaths:Server Log = "/Library/Logs/Mail/mailaccess.log" mail:logPaths:POP Log = "/Library/Logs/Mail/mailaccess.log" mail:logPaths:SMTP Log = "/var/log/mail.log" mail:logPaths:Migration Log = "/Library/Logs/MailMigration.log" mail:logPaths:Virus Log = "/Library/Logs/Mail/clamav.log" mail:logPaths:Amavisd Log = "/Library/Logs/Mail/amavis.log" mail:logPaths:Virus DB Log = "/Library/Logs/Mail/freshclam.log" mail:imapStartedTime = "2012-07-30 18:14:26 +0000" mail:servicePortsAreRestricted = "NO" mail:state = "RUNNING" mail:postfixStartedTime = "2012-07-30 18:14:49 +0000" To stop the service: sudo serveradmin stop mail And to start it back up: sudo serveradmin start mail To configure some of the settings no longer in the GUI from previous versions, let’s look at the full list of options: sudo serveradmin settings mail One that is commonly changed is the subject line added to messages that are marked as spam by spam assassin. This is stored in mail:postfix:spam_subject_tag, so changing would be: sudo serveradmin settings mail:postfix:spam_subject_tag = "***DIEEVILSPAMMERSDIE*** " A number of admins also choose to disable greylisting, done using the mail:postfix:greylist_disable option: sudo serveradmin settings mail:postfix:greylist_disable = no To configure an email address for quarantined mail to go, use mail:postfix:virus_quarantine: sudo serveradmin settings mail:postfix:virus_quarantine = "diespammersdie@krypted.com" The administrator, by default, doesn’t get an email when an email containing a file infected with a virus is sent through the server. To enable this option: sudo serveradmin settings mail:postfix:virus_notify_admin = yes I also find a lot of Mac environments want to accept email of pretty much any size. By default, message size limits are enabled. To disable: sudo serveradmin settings mail:postfix:message_size_limit_enabled = yes Or even better, just set new limit: sudo serveradmin settings mail:postfix:message_size_limit = 10485760 And to configure the percentage of someone’s quota that kicks an alert (soft quota): sudo serveradmin settings mail:imap:quotawarn = 75 Additionally, the following arrays are pretty helpful, which used to have GUI options:
  • mail:postfix:mynetworks:_array_index:0 = “127.0.0.0/8” – Add entries to this one to add “local” clients
  • mail:postfix:host_whitelist = _empty_array – Add whitelisted hosts
  • mail:postfix:blacklist_from = _empty_array – Add blacklisted hosts
  • mail:postfix:black_hole_domains:_array_index:0 = “zen.spamhaus.org” – Add additional RBL Servers
The client side of the mail service is straight forward enough. If you are wondering where in this article we discuss using webmail, er, that’s not installed by default any longer. But the open source project previously used, roundcube, is still available for download and easily installed (the pre-reqs are all there, already). Check out the roundcube wiki installation page here for more info on that. Also, mail groups. I hope to have a post about that soon enough. Unless, of course, I get sidetracked with having a life. Which is arguably not very likely…

July 31st, 2012

Posted In: Mac OS X, Mac OS X Server, Mac Security

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I originally posted this at http://www.318.com/TechJournal Mailbfr, spamtrainer and amavis-stats are great packages that fit into Mac OS X Server. The guys from topicdesk have been kind enough to post an overview on how their products work under Leopard and how the changes in Leopard impact their utilization. Check it out at: http://osx.topicdesk.com/content/view/129/1/

November 5th, 2007

Posted In: Mac OS X Server

Tags: , , ,

Here’s an article by Dean Shavit (formerly of MacTek) on tricking out your SquirrelMail: http://www.mactech.com/articles/mactech/Vol.21/21.08/SquirrelMail/index.html

September 18th, 2007

Posted In: Mac OS X, Mac OS X Server

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