During a traffic audit, it becomes very critical to know exactly what you are looking at. I often refer to this document. A very important consideration to those new to the field: IANA does not enforce these assignments. They are only here to be the official registry. Just because you see a specific port being used, doesn’t absolutley mean that port is carrying it’s assigned traffic. Worms will often use well-known ports to disguise themselves. Rule of thumb: always analyze the packets, don’t just assume based on the port.
The Ubuntu Forums are very valuable as a reference tool. It always helps to read an entire thread before implementing things, due to the assistanceit provides being user-generated content. It saved numerous reinstalls when I first started using Ubuntu.
When I went searching for this site, I was guided to a link informing me that all documentation would be merged to the support site. Clicking on that link, directed me to a redirect to the “New” support site. (kind of Monty Python-ish, I know). Regardless of where it is and what it is called, Cisco has stellar documentation for IOS and all of their products online for brushing up on your skills.
This is the place I go as a darkhorse search of last result for information about open source troubleshooting. It’s not due to a lack of information or quality. Linux Forums has been around for 10+ years and I remember using it intensly to learn about Red Hat and Mandrake Linux. It is still a high traffic site and if I have a question regarding RPM-based distributions, I will still frequent it. The usual warning about reading an entire thread applies here as well. Become an expert, not just someone looking for a quick fix.
The name says it all with this one. Debian has a strong library of resources to learn how to implement solutions and resolve problems in this distribution.
This is the default place I look for domain owner information. It is always handy to have access to this in a situation where your customers are using third party services that provide specialized solutions.
Do you have any suggestions for any other sites that help make your day as an IT Admin? Please feel free to suggest your own favorites in the comments section.