The functional layers for swiching environments in the Data Center are often architected around three layers, commonly referred to as The Cisco Three-Layered Hierarchical Model: The Core Layer connects the Aggregation Layers. Typically, the Core Layer utilizes high performance low latency Layer 3 switches (often 10 gig Ethernet and/or 10 gig fiber). The Aggregation Layer provides services, such as Load Balancing and SSL Optimization. Access Layer switches typically use the Aggregation Layer for connecting to the Core Layer. The Access Layer includes the hubs and switches that connect client systems.
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Dual WAN Connections
I originally posted this at http://www.318.com/TechJournal Often, a single internet connection is all that is needed to allow a group of computers to access the internet for websites, email and chatting. DSL, Cable Modem or a single T1 can often provide enough bandwidth for a small group of users. As your company grows, there can come a point where the speed of the internet connection becomes a bottleneck, increasing the time for web pages to load and for emails to be sent and received. After you hit the limits of what a single connection is able to provide, one very cost effective way to address the issue is to add…
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Mac OS X 10.5 Server: PDC Emulation and Domain Admins
Creating a Domain Admins group article on AFP548.com: http://www.afp548.com/article.php?story=200608252114039
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Packet 8
I originally posted this at http://www.318.com/TechJournal Voice over Internet Protocol (VoIP) is the technology used to transmit voice conversations over data (computer) networks using the Internet. The data network can be T-1, DSL, Cable Modems or any other high-speed Internet (broadband) connection. In the past few years, Vonage took the country by storm, offering low cost unlimited long distance using VoIP. For most residential users, Vonage is perfect. Vonage is easy to setup and use and has all of the features a standard phone would have for a fraction of the cost for most people. ViaTalk, Sun Rocket, ITP, Lingo, SpeakEasy and TalkTimes.net are all competitors to Vonage, but while…
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WAF: Web Application Firewall
Web Application Firewalls, or WAFs, are firewalls for web application. They monitor web traffic and decide whether to allow or deny specific requests. IIS web servers (OWA), Apache, WebObjects, Lasso and other web servers will likely end up working with them, although I’ve only tested IIS and Apache at this point.
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Host Defined
You may hear me use the word host a lot. When I say host I mean a computer that is connected to a network. Depending on the environment, the host can provide centralized control of the network or be a client, a server, both a client and a server, etc.
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Using a + in an email address
If you take an email address like my iCloud account, it’s krypted@me.com. If I take the username and add a + at the end I can then type some characters and put it all in front of the @ and domain name then the mail will still come to me. So, let’s say I use it to create an AppleID for an APNS certificate. That would be: krypted+apns@mac.com Or iTunes: krypted+itunes@mac.com Or iPhone1 (or these days iPad1): krypted+ipad1@mac.com The only gotcha is that occasionally you’ll run into some field on a webpage that has input validation for non alpha-numeric characters. Shouldn’t be the case, but it comes up from time…
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Tired of Hosting Your Own DNS?
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SBC Spam Prevention Falls Short
SBC sends all their residential customers port 25 traffic to their mail server, regardless of the destination IP number, regardless if dial up, DSL, etc. Expect this trend to continue to other vendors with residential accounts to help combat spam. IMHO killing spam by effectively blocking out port 25 for end-users is not a huge deterrent of spam.
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Xsan: Metadata Network
Xsan needs an out-of-band metadata network. This network is used to transfer information, or metadata on files being written to the SAN. The metadata network on an Xsan should be low latency. Nothing should potentially interfere with the transfer of data. Therefore, make sure that you disable all the management features of your switch. But make sure it’s a good switch. I prefer to use a managed switch, disabling all the management features.