Q: What is the naming convention for Cisco IOS releases?

A:

Cisco has a white paper which explains how the release names work.

Q: How do I upgrade IOS on a 2600 series router?

A:

Inteructions are here at cco.

Q: How do I configure Layer 2 security on a 3550?

A:

This article here explains it.

Q: How do I view and clear err-disabled switchports on a 3550?

A:

On the 3550, the command #sho int status will print a table of interfaces, with status. The status may be "err-disabled". To investigate such ports, use #sho int status err. To clear the port status, issue a (c-i)#shut and then a (c-i)#no shut on the interface. Or, you can enable autorecovery after a time period. Use these commands to check your current autorecovery config:

#sho errdis detect
#sho errdis flap-val
#sho errdis recovery

To enable autorecovery for a particular cause, use

(c)#errdis recov cause {cause}

Q: Why are only my eBGP-learned routes getting redistributed into OSPF, while the iBGP-learned routes are not?

A:

Cisco has added a "safety feature" to BGP in order to, they say, prevent possible accidental routing loops. I think this is unnecessary, as anyone configuring BGP should already be knowledgeable enough to set up route redistribution correctly. Anyway, your router won't redistribute any iBGP routes into OSPF unless you add the following directive to the ROUTER BGP section: bgp redistribute-internal

Q: Where do I go to download IOS versions?

A:

Cisco has a tool called the IOS Upgrade Planner which allows you to drill down to IOS releases by version number, platform, and title. This is useful if you already know what you are looking for.

Q: How do I determine what version of IOS is needed to support a particular command?

A:

The Cisco Feature Navigator page has links to tools which allow you to browse IOS versions. You might find what you need using one of these tools.

Q: How do these posts look?

A:

These posts look almost exactly like this.