This week I've started setting up a VOIP lab to explore the technology and when I'm done, I plan to integrate it into my home network. So far I've purchased the following for my lab... c1760-V 192D/48F PVDM-12 VIC-2FXO VIC-2FXS running … [Read more]
OS X Leopard Hacks
Here are a few settings you can change using the OS X defaults command to access some system parameters. As always, proceed with caution, and don't mess with things of which you have no clue. I have only verified these in OS X 10.5 - no promises if … [Read more]
Demystifying Cisco Config Register Bits
Ever accidentally set your config register to a random value that isn't in the Cisco documentation? No? Neither have I, but one day I encountered someone on #cisco that had. So I did my best to help him, and was able to decode his settings and get … [Read more]
Securing SSH against bruteforce attacks
This is one of the methods I've used in the past to secure a Linux host against brute force ssh attacks. While its not a perfect method, it does a good job of preventing 100s of brute force entries in your syslog. … [Read more]
Regular Expression Basics
Before I even get started, I want to mention that not all regular expression metacharacters are supported in every application. Keep this in mind when building your matches. Regular expressions are made up of normal characters and metacharacters. … [Read more]
Cisco IOS Tips and Tricks
So, I'm sure these have been posted almost on every networking blog under the sun, but who knows, right? Here are a few tips and tricks to help you move around the IOS a bit faster, find information faster, and locate problems... faster. … [Read more]
Working on my new lab setup
So, I purchased a couple extra routers, and a second layer3 switch from @usedciscoguy. He gave me a really good deal and I plan on purchasing a 6500 series switch from him as soon as I can afford it. Anyway.... I've spent a little bit of time working … [Read more]
Layer 2 Ethernet transport over OpenVPN
One of the things I used to deploy frequently at my previous position was transport for other ISPs and businesses. Since MPLS support is in its infancy on the Imagestream platform, and was yet to be deployed at the time, this is what I came up with. … [Read more]
Using OSPF to create unlicensed full duplex connections.
Recently one of my clients asked me to help resolve an issue at an aggregation point on their network. They had several connections that converged onto a single unlicensed link on their network, not only was the link saturated, but it had lots of … [Read more]
How does latency effect throughput?
One of the questions I get asked several times a week by my clients is as such. While most people never associate latency with the amount of data they can send across a single TCP stream, engineers need to understand this concept. Luckily, someone … [Read more]
