Loopback Mountain

Good post on the little-known computer crime wave targeting small/medium businesses: http://www.krebsonsecurity.com/2010/01/buried-warning-s...

During a recent IOS upgrade on a Catalyst 3560, I was connected to the console and noticed that the reload was taking much longer than usual...

One of the things you need to look at when designing networks with Catalyst switches is the potential for TCAM exhaustion due to ACL and QoS...

A few days ago I posted an amusing comment on Ivan Pepelnjak's always excellent Cisco IOS Hints and Tricks blog, and he found it funny e...

I had an interesting troubleshooting experience that showed me that I didn't fully understand how incoming dial-peers work with POTS lin...

I use these constantly (and many others, but these come first to mind): display only interfaces with assigned IP addresses: sh ip int b | e ...

I was helping a friend study for CCNA the other day and saw a RIP behavior I'd never noticed before. I knew that RIP keeps a local route...

I've been doing Cisco IDS/IPS stuff recently for the first time in a long while. If you haven't tried Cisco's new free IPS Manag...

Haven't posted here in ages. Interesting trivia: the old "show ip sockets" command doesn't work in new 12.4T images. It...

In the free verison of ESXi, it's not obvious how to clone a VM, since you don't have VirtualCenter available. I've read about s...

This works on both Ubuntu and Xubuntu. Use sudo on everything or run as root. apt-get install libncurses5-dev g++ bison flex apt-ge...

dig is the standard tool for advanced DNS queries. A Windows version is available as part of the BIND port. To install it on Windows: 1)...

Ever forget what port number maps to what service? A router running Adv IP Services, Adv Security, or Adv Enterprise Services will tell you ...

Many people don't realize that reasonably recent versions of IOS have in-line ACL editing. The way this works is that ACLs have invisibl...