10 Killer Open Source Networking Tools
If you have faced the problems like you copied and pasted a new configuration into a router or switch and it stops responding, and you don’t remember old configuration, then here’s your bet- RANCID.
RANCID (Really Awesome New Cisco ConfIg Differ) is a versioning system for your switch and router configurations. It uses either CVS or Subversion to store each new version of your configuration files. As it gathers and stores the configuration for each of your devices, it runs a difference against the previous version to see what, if any, changes have been made. When it detects a change, it sends out an email with the details of that change to an address of your choosing. With RANCID, you'll know whenever a change has been made by your NOC team.
One of the neat features of RANCID is that it includes a looking-glass server. You can take a quick peek at all the routes in your organization and search for any elements that are out of sorts when you suspect a routing problem on your network.