rsync throwing odd error

[John Almberg]

This is the week for strange problems...

I use rsync to copy tinydns data files to backup name servers. This  
has been working for about a year with no problem. Suddenly, I am  
getting odd errors:

/usr/local/bin/rsync -az -e 'ssh ' data.cdb admin at qu.example.com:/usr/ 
local/etc/tinydns/root/data.cdb
channel 1: open failed: administratively prohibited: open failed

The rsync does work. That is, the file is copied over. So this is  
actually a warning, I guess.

On the other server, the one the file is being copied TO, the  
following is printed in /var/log/auth.log

Nov 21 12:43:38 qu sshd[4604]: Address 67.111.0.194 maps to  
on.example.com, but this does not map back to the address - POSSIBLE  
BREAK-IN ATTEMPT!
Nov 21 12:43:38 qu sshd[4604]: Accepted publickey for root from  
67.111.0.194 port 55777 ssh2

I'm guessing this is some sort of DNS mis-match, but I don't quite  
grasp what the problem could be.

Again, this did work without error or warning until recently.  
Something has changed, but not the DNS records.

I'm stumped. Any ideas much appreciated. (I have changed the  
addresses in the examples above to protect the innocent (me!)

-- John