Re: openssh public key (after upgrade) problem

["Andrew M.A. Cater" <amacater@galactic.demon.co.uk>]

Fixed. The machine had moved subnets so changed IP address. Buried in 
/etc/ssh/sshd_config was the answer: I'd carefully been security aware 
and set the machine ListenAddress to it's actual IP address i.e. 

ListenAddress 192.168.1.2
Protocol 2

Two years or so later, I'd forgotten all about this :) Once I'd brought 
in the latest Debian OpenSSL and the OpenSSH which incorporates 
blacklisting, I regenerated all my keys and then checked the sshd 
config. Change to the actual IP address now:

ListenAddress 192.168.10.1

and all was well - users could log in again. The hard bit was working 
out why SSH was effectively "one way" when the machine could SSH 
outwards fine.

You live and learn, so I thought I'd document this here so that other 
people can find it easily.

AndyC