I have worked with Cisco routers off and on for several years. My role recently changed at my company, and now I am the primary person responsible for our Internet router. We had the router fail just after I joined the company and then I found out that no one had the password for the router. Cisco had to walk us through the password recovery process. I realized quickly that I need to know a lot more. How should I proceed ?
- Via the Internet
 
I would recommend looking through your local bookstore and start going for your Cisco Certified Network Associate certification. This will give you some good exposure to what your Cisco router is capable of. Study the book in combination with either a spare router or a good router simulator and that should get you very comfortable with the Cisco IOS command-line interface in a non-production environment. Better to make your mistakes in a non-business-critical environment when possible.
 
I would strongly suggest implementing SSH (Secure Shell) on the router if possible. This will help avoid your router getting hacked through the telnet interface and keep remote access as secure as possible. This will require that the IOS on your router have some degree of IPSec (either Data Encryption Standard or Triple-DES) installed. Depending on the type of IOS you have, you may need to look at an upgrade in order to be able to implement SSH.
 
Make it a regular practice to do a copy run start every time you make a change to the router so you've saved the changes you have made. As simple as this seems, I had to deal with a major ISP on behalf of a customer several years ago who forgot to do this more than they remembered, so I learned this lesson painfully. As a part of saving the config, be sure to save a copy of the config in a text file somewhere you can get to easily so if you have to replace the router or reprogram it from scratch you won't have to type it in line by line.
 
You'll find that the IOS has a good logging system built in. You will see two service stamp entries when you do a sh run, one for log and the other for debug. Re-enter these lines with a msec option. This adds a milisecond counter to the time stamp to make it easier to get a better level of granuarity, so you will know exactly when an item appeared, if you have items hitting in the same second of time. Implementing NTP will make the logs really useful for you. This is just scratching the surface of what you can do, but it will get you started.