Sendmail name lookup issue
I am having some strange issues with sendmail at the moment.
When a mail comes into my sendmail server, where it is then relayed onwards, the sendmail server for whatever reason tries to forward it a hostname that it shouldn't.
Have no idea where it gets this hostname from in the first place as it should be sending it to a mail.full.domain.name server.
So my question is, does anyone exactly know how sendmail performs a hostname or DNS lookup and where it's cached. The strange thing is though that a restart of the sendmail service fixes this, yet it reappears sometimes, usually when we have some network issue in the back-end.
One would think that sendmail would clear its cache every few minutes. Or does it leverage something else to perform this lookup.