SSH identity changed on new Server - can't login over SSH!

feenster99 · 2 Jan 2008 at 16:53

Hi all,
I run a Ubuntu data server, with clients rsync'ing their data onto it via SSH. This was running 6.10, but i've upgraded to 7.10 today.

Everything has gone fine except that the SSH identity of the Server has changed. As my clients use password-less authentication using private keys, this is a bit of a pain as no-one can send any data (we use custom made software that doesn't give them the opportunity to accept the new host).

Is there any way to change the SSH identification back to what it was? I installed 7.10 on a new hard drive, so everything else from the working install of 6.10 remains intact. The IP address and hostname are the same too.

Any help would be greatly appreciated.

Matt

FirebarUK · 2 Jan 2008 at 18:29

I would imagine its somewhere in the .ssh folder and one of the files in there. If you know the old host identity I guess you could overwrite it. Otherwise tell your clients to simply remove the machines entries from their .ssh/authorised_keys file.

I'm presuming all of the private keys etc were put back in place and the different host ID is the only problem..

feenster99 · 2 Jan 2008 at 19:02

After some help on another forum, it was as simple as copying /etc/ssh/ssh_host_* from the old to the new system. Once that had been done, it worked fine.

Thanks for the reply :-)

Matt

FirebarUK · 2 Jan 2008 at 19:12

Handy you had it backed up somewhere safe

feenster99 · 2 Jan 2008 at 19:16

Well as it's a critical server, and it's a relative new release, I thought i'd just do it on a new hard drive. Glad i did now

Matt

Garp · 2 Jan 2008 at 19:31

Theoretically, its supposed to backup all config files when it does an upgrade, however that does really depend on whether the package maintainers created their db package the correct way or not. Before doing an upgrade always backup critical data, and also its worth tarring a copy of the etc folder up

Code:

tar cvjf /etc.BKP$(date +"%Y%m%d").tar.bz2 /etc

To be honest.. if its a critical server, can I ask what the rational was for the upgrade? 6.10 seems a bit of an odd choice too, 6.06 with its LTS would be more logical, unless there is specific versions or a hardware incompatibility there?

feenster99 · 2 Jan 2008 at 19:48

The rationale was that the original install of 6.10 had become messy. I'm not bothered about the LTS release, as this server will be replaced long before the support runs out.

Matt