Posted on in System Administration
Every machine needs a name. As soon as the second server is ready to go, the name SERVER no longer seems like a great idea. When deciding how to name servers, there are two primary conventions: functional names and unique names.
Functional names take the job assigned to …
Posted on in Networking
<acronym title="UniDirectional Link Detection">UDLD</acronym> is a Cisco protocol designed to detect and disable unidirectional links in Ethernet (fiber or twisted-pair). In the case of a radio-based Metro Ethernet ring, UDLD goes the extra mile in preventing Spanning-Tree loops and user service interruption.
In this simple network of …
Posted on in voice
When using Asterisk and a remote bank of <acronym title="Primary Rate Interface">PRI</acronym>s (or any other form of <acronym title="Public Switched Telephone Network">PSTN</acronym> connectivity for that matter), you may encounter an issue known as hairpinning. Hairpinning describes what happens when a call coming from …
Posted on in System Administration
A buddy of mine was recently setting up a new installation of Courier with virtual user support via MySQL. He ran into an issue when trying to get authdaemond to connect to a remote MySQL installation. No matter what he changed in authmysqlrc, the following kept appearing in his mail …
Posted on in System Administration
If you're like me, it probably seems obvious that command logging is an important part of system administration. Any change I make, whether it's on a router or server, is logged somewhere. Although folks give plenty of reasons why they don't use tools like sudo for super-user functions (inconvenience and …
Posted on in System Administration
Note: I recently had to prepare a Mac mini for use as a network testing device. The system was installed in a remote location and only reachable via SSH.
Important commands: hdiutil, installer, softwareupdate, shutdown
When preparing a system for production, there are three main tasks that need to be …
Posted on in Graphics Design
I thought I should give credit where credit is due.
Making PNGs with alpha-channel transparency in Photoshop
I used David Chess' tutorial on PNG alpha-channel transparency in Adobe® Photoshop® to create the Slaptijack sandwich logo. When I first started working on the logo, I was completely lost. I knew I …
Posted on in System Administration
Posted on in Networking
It used to be that access lists in Cisco IOS were numbered. Not only were they numbered, but the numbers were significant to what kind of access list they were. Now access lists (and just about everything else) can be named rather than numbered. Although this seemingly innocuous change has …
Posted on in Software
I recently started using ScribeFire as my blogging client. Here are some initial thoughts on it.
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