Routing gotchas

[deanwebb]

If you're working on a routing problem, what are some common pitfalls that you have to watch out for?

[that1guy15]

-ALWAYS use route-maps when redistributing into a routing protocol. ALWAYS!!
-Changing config on the interface you are connecting in with - Always use "Reload in XX" or you will have a drive of shame
-For routing protocols make sure you have auto-summary disabled. What,you just advertised the whole companies 10.x.x.x space out that 2911 T1!?!
-Test your AAA configuration before logging out.

[Seittit]

Make sure you specify the word "subsets" when redistributing into/out of OSPF.
Make sure you set the metric when redistributing into/out of EIGRP.
Make sure to fire the guy that designed the backbone routing with iBGP


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[wintermute000]

you mean subnets

Don't ever delete an ACL, prefix list, community list, or whatever without a show run | include (name) first to make sure its not applied anywhere.....
Always check what you are pasting - I paste into notepad first to make sure the clipboard contents are correct.
Turn off that right click to paste option in putty. Seriously who thought that was a production worthy idea?
Always log your terminal sessions and always start any config work with a show run.
Never paste huge chunks of config in one go, always paste a paragraph or three at a time especially in console. Stuff doesn't always paste properly, pasting too much makes it really easy to miss errors.
A rollover cable from a router AUX port makes a great out of band console cable for another device in a pinch (as long as you can get to that router!), make sure your field guys carry them - google reverse telnet.
Always check md5 on any image you flash before you do the reload.

Also configure revert is a good alternative to reload in 10 in most cases - though it ain't a reload, and some scenarios do benefit from a reload (e.g. re-establish adjancies, clear XYZ etc.) but in general its a quicker, less outage-causing substitute