I have lots of "lame server" messages on my security log.

What are these?

Thanks.

These are from DNS reverse lookup, it tries to get a domain name from the IP address (see your DNS zone file). The errors indicate that the servers for these sites are mis-configured.

What kind of mis-configuration?

I guess it has something to do with badly configured reverse DNS. ;-)

I have tried DNS zone cleanup within WHM, do you think that might sort it?