[CentOS] ssh reverse DNS failure

I use dyndns's (free) service to access a remote machine
with a dynamic IP address.
The machine is running under CentOS-6.0.

I can ssh into the address given me by dyndns (*.homelinux.com),
but when I do this I get the warning
"reverse mapping checking getaddrinfo for" * 
  "failed - POSSIBLE BREAK-IN ATTEMPT!"

This doesn't really matter,
as I normally use OpenVPN for accessing this site -
the dyndns method is a safety precaution in case openvpn doesn't work.

But I'm wondering if it is possible to stop the warning?
I've tried various recipes google gave me,
eg adding "UseDNS no" to /etc/ssh/sshd_config on the remote machine
(and re-starting sshd),
but none of them has worked,


-- 
Timothy Murphy  
e-mail: gayleard /at/ eircom.net
tel: +353-86-2336090, +353-1-2842366
s-mail: School of Mathematics, Trinity College, Dublin 2, Ireland