public key not valid anymore after update to 16.04

Karl Auer kauer at
Mon Mar 28 08:47:40 UTC 2016

On Mon, 2016-03-28 at 09:58 +0200, robert rottermann wrote:
> I updated my ubuntu 15.10 box to 16.04 beta.
> Now my public keys do not "work" any more. I can not log into any of
> the remote machines I could before.

You should still be able to log in, but you will be asked for a
password. If you are not asked for a password, then the remote systems
are probably not allowing password logins. If you are asked for a
password, but a known good password does not work, then you have a
different problem.

Are your keys still there? That is, in ~/.ssh?

If not, backup whatever is there, restore your backed-up keys to ~/.ssh and try again. If you don't have a backup you are screwed and will have to cut new keys.

Do you see any error messages? If not, add the parameter "-v" to your ssh command line and try again. Look for clues in the output. Send us the output (sanitise it first if you wish). The more "v"s you add, the more detail you see. Up to three :-)

Your host key may have changed, so check the configuration at the other end; look especially for "Match" statements.

> Is there a way to fix that without generating new keys?

Unless you have managed to lose the keys and have no backup, that
really should not be necessary.

Regards, K.

Karl Auer (kauer at

GPG fingerprint: E00D 64ED 9C6A 8605 21E0 0ED0 EE64 2BEE CBCB C38B
Old fingerprint: 3C41 82BE A9E7 99A1 B931 5AE7 7638 0147 2C3C 2AC4

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