Paolo Supino a écrit :
Hi I didn't think of checking if Sendmail is the one sending the email or not. I will have to check this out. I will only have access to this server next Wednesday. So until then I can't check anything or post anything ...
If you find that it's sendmail, use alternatives to set the MTA to postfix instead (and stop Sendmail as you don't need it anymore, and having two different MTAs on a box generally results in surprises).
if that's not the problem, ask on the postfix-users list. There show the output of 'postconf -n' and relevant logs. you can hide private domains and IPs but do so coherently (use example.com, example.org, example.net or whateveryouwant.example for domains, and use 192.0.2.* for "public" IPs. but make your substitution a "one to one" mapping).