The Boston Diaries

The ongoing saga of a programmer who doesn't live in Boston, nor does he even like Boston, but yet named his weblog/journal “The Boston Diaries.”

Go figure.

Saturday, November 21, 2009

Woo hoo, Cisco!

We finally installed a new Cisco router to replace our last Riverstone router in our network. I pre-configured the router and the replacement went fairly smoothly.

In, out, nobody got hurt. Just how I like it.

Later on I go to log into the router (to backup the configuration):

[spc]lucy:~>ssh core02.rt.bct.XXXXXXXXXXX
The authenticity of host 'core02.rt.bct.XXXXXXXXXXX (XXXXXXXXXXXXXX)' can't
be established.
RSA key fingerprint is f0:3f:06:c8:ee:7d:40:55:38:57:a4:5c:bd:d6:81:a2.
Are you sure you want to continue connecting (yes/no)? yes
Warning: Permanently added 'core02.rt.bct.XXXXXXXXXXX,XXXXXXXXXXXXXX' (RSA)
to the list of known hosts.
ssh_rsa_verify: RSA modulus too small: 512 minimum 768 bits

What the?

Turns out that ssh 2 requires a minimum key length of 768 bits, but Cisco defaults to key lengths of 512 bits.

Way to go, Cisco! Woot!

To get in, I just logged into an adjacent router, then used that router's version of ssh (which works just fine with 512 bit keys, breaking the ssh 2 standard), which allowed me to clear the existing key (crypto key zeroize rsa) so I could regenerate a larger key.

Obligatory Picture

[“I am NOT a number, I am … a Q-CODE!”]

Obligatory Contact Info

Obligatory Feeds

Obligatory Links

Obligatory Miscellaneous

You have my permission to link freely to any entry here. Go ahead, I won't bite. I promise.

The dates are the permanent links to that day's entries (or entry, if there is only one entry). The titles are the permanent links to that entry only. The format for the links are simple: Start with the base link for this site:, then add the date you are interested in, say 2000/08/01, so that would make the final URL:

You can also specify the entire month by leaving off the day portion. You can even select an arbitrary portion of time.

You may also note subtle shading of the links and that's intentional: the “closer” the link is (relative to the page) the “brighter” it appears. It's an experiment in using color shading to denote the distance a link is from here. If you don't notice it, don't worry; it's not all that important.

It is assumed that every brand name, slogan, corporate name, symbol, design element, et cetera mentioned in these pages is a protected and/or trademarked entity, the sole property of its owner(s), and acknowledgement of this status is implied.

Copyright © 1999-2024 by Sean Conner. All Rights Reserved.