• Mac OS X Server

    Configure The Mail Service In macOS Server 5.4

    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…

  • Mac OS X,  Mac OS X Server,  Mac Security

    Configure The Mail Service In macOS Server 5.2

    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 5.2 for Sierra, 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 the former systems administrator of a large number of mail servers, I firmly believe that there is a special kind of hell where only spam is…

  • Mac OS X Server

    Configure The Mail Service in OS X Server 5

    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…

  • Mac OS X,  Mac OS X Server,  Mac Security

    My Own List of Common Apple Ports

    I’ve been underwhelmed (if that’s a word) by the list of common ports used on the Apple platform recently, so I started my own. It’s available at https://krypted.com//guides/common-apple-ports/ if you’re interested. It’s also under the Tools menu of the site. And yes, I’m aware that I can cat /etc/services; this includes some rudimentary notes.

  • Mac OS X,  Mac OS X Server,  Mac Security,  Microsoft Exchange Server

    Configure The OS X Yosemite Server Mail Service

    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…

  • Kerio,  Mac OS X,  Mac OS X Server

    Configure the Mail Service in Mavericks Server

    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…

  • Microsoft Exchange Server,  Windows Server

    Resolve 530 5.7.1 Client was not authenticated Error In Exchange 2010-2012

    When working on mail flow issues, one of the first troubleshooting steps with any mail server is to try and telnet into port 25 of the server. Exchange has an error, 530, that says that the smtp connection wasn’t authenticated. If you’re trying to relay through an Exchange server, that’s a good thing, as you wouldn’t want an open relay. However, if you’re trying to relay to an Exchange server, that’s not such a good thing. So let’s look at what this symptom looks like. First we try and telnet into port 25 of the server: telnet exchange.krypted.com 25 Which shows the following: 220 exchange.krypted.com Then we say hi: Helo…

  • Microsoft Exchange Server,  Windows Server

    Create An SMTP Tar Pit In Windows Server/Exchange

    Windows Server has a role that it can run in SMTP. Exchange and other services use this role to relay mail. There is a type of attack against a mail server that revolves around effectively performing a Denial of Service (DoS) against Exchange by sending massive quantities of mail to the server and forcing it to send Non Delivery Reports (NDRs) from the mail you’ve sent the server. This is known as an NDR Flood Attack. You can also leverage what’s known as a Directory Harvest Attack to get a server to respond to each possible combination of characters for addresses on domains running on an Exchange server. A Directory…

  • Kerio

    Kerio: Spam Options

    Kerio has a variety of features available for mitigating the evil spam gremlins.  These include: 1 – SpamAssassin – Open Source spam filter 2 – Directory Harvest Attack Protection – track email coming in for non-existent users and limit the number allowed per host 3 – Policies – tag emails with X-Spam headers, then use local policies, etc.  Also write custom filters that identify certain keywords as spam 4 – RBL – A standard with mail servers, Realtime BlackList servers mark common spammers or hosts that do not meet a minimum criteria for being acceptable mail servers 5 – SPF – Rely on srv reccords from domains to specify what IPs…

  • Mac OS X

    Mac OS X: Setting up Outgoing Accounts with Mail.app

    Incoming and outgoing mail are handled a bit differently from one another in Mail.app. This is helpful as you can have multiple outgoing accounts even if you only have one incoming accounts, useful if you move between a lot of different networks.  To setup a new SMTP account, open the Accounts pane of the Mail.app preferences and choose Edit Server List… from the Outgoing Mail Server (SMTP): field. At the Server List screen click on the “+” icon and enter a description for the account. This can be anything to help the end user remember what this account is meant for. Then type in the name or IP address of…