de mi a fene van már komolyan...
main.cf-be beraktam ezt:
disable_dns_lookups = yes
Assuming that present day Ubuntu servers typically use Postfix as the message transfer agent, it is possible to tell Postfix to disable DNS lookups for SMTP with disable_dns_lookups configuration parameter. Add the following line
disable_dns_lookups = yes
to the Postfix's configuration file located at /etc/postfix/main.cf. This will make Postfix look into /etc/hosts when it tries to resolve the domain address of a mail recipient.
