Re: Problem with SSH host keys

[Rob Owens <rowens@ptd.net>]

----- Original Message -----
> From: "Keith Lawson" <keith@nowhere.ca>
> 
> Hello,
> 
> I'm running jessie on my laptop and after doing a dist-upgrade yesterday
> I'm getting SSH host key errors for a bunch of servers I've been
> connecting to for years:
> 
> The authenticity of host 'blah' can't be established.
> RSA key fingerprint is e8:08:db:b0:e7:38:57:d4:82:a8:a4:1c:42:f0:25:09.
> Are you sure you want to continue connecting (yes/no)?
> 
> The host keys are in ~/.ssh/known_hosts and haven't changed on the
> server side. Looking at the openssl, openssh-server and openssh-client
> change logs I don't see anything that would explain this behavior. Is
> anyone aware of any changes in openssh-client in jessie that would cause
> certain server keys that were previously working to be invalid?
> 

I just tried ssh'ing from my jessie server and couldn't reproduce your problem.  Usually if the key has changed, you get a different warning "someone is doing something nasty", or something to that effect.  The message you're getting seems to indicate it's not finding the host/fingerprint in known_hosts at all.  Check the permissions on known_hosts.  On my system it's 600.  Also check ~/.ssh -- it should be 700.

You can check the fingerprint in the known_hosts file like this:

ssh-keygen -F blah -l

Compare this value to the fingerprint being reported in the message you posted above.

-Rob