topic SSH Still Working after Hostname change??? in Network Security

SSH Still Working after Hostname change???

David_Mitchell — Fri, 21 Feb 2020 13:04:56 GMT

Hi all,

I was under the impression (from past experiences) that SSH self-signed certificates are made up of the Hostname and the Domain Name of the router.

I have been working on a customer network and I can see that the SSH RSA certificate is using the old hostname of the device+domain name but SSH still works both inbound and outbound on the VTY lines!

I thought you had to zeroize the keys and recreate using the crypto key generate rsa command in order to continue to use SSH after a hostname change so that the new certificate contains the new hostname?

Any explanation would be greately appreciated

Many thanks

David

SSH Still Working after Hostname change???

Carlo Poggiarelli — Thu, 09 Jan 2014 09:13:11 GMT

Hi David.

Yes after changing router parameter such as Hostname, domain name SSH still works with the old certificate.

What i can suggest you is to recreate it through crypto key generate rsa command in configuration mode.

HTH

Regards

Carlo

SSH Still Working after Hostname change???

David_Mitchell — Thu, 09 Jan 2014 10:59:55 GMT

Thanks for confirming Carlo, this had to be the case as I am seeing it work with old certificate but I just needed to check as I thought in the past I had to re-generate the cert first. Thanks again