Server Fault is a question and answer site for system and network administrators. Join them; it only takes a minute:

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

I'm configuring a Cisco 3640 and it's not saving simple things like my hostname.
I've tried with 'wr' and 'copy running-config startup-config'. Also erased the configuration but no luck.
There's no error whatsoever when running the above commands.
Is my flash bad? Anyway I can debug this more thoroughly?


share|improve this question
up vote 6 down vote accepted

It sounds like you have a configuration register at the wrong setting. For instance, setting: confreg 0x2142 at an rommon will boot the router to a fresh/default mode. Trying entering config-register 0x2102 from an enable prompt to got back to booting from your configuration

share|improve this answer
Right you are! Thanks. – Colin Feb 9 '10 at 19:47

Rommon is probably set to ignore the startup-config.

Do a 'show version' and see if the configuration register is 0x2142. If it is you will have to change this to 0x2102.

Edit: Points to Andy he posted first.

Someone got half way through a password reset and gave up.

share|improve this answer

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.