Postfix Temporary lookup failure

Solution 1:

mynetworks needs strict network ranges

In my case, there was a wrong ip range in /etc/postfix/main.cf.

# Wrong; Temporary lookup failure
mynetworks = 172.16.0.0/8
# OK
mynetworks = 172.16.0.0/12

There was an error in /var/log/maillog that I noticed later.

Oct 4 13:47:54 postfix/smtpd[25056]: warning: non-null host address bits in "172.16.0.0/8", perhaps you should use "172.0.0.0/8" instead

If someone comes here from the top hit on google with searching Temporary lookup failure, I'd say please dubble-check your $mynetworks format.

Solution 2:

Run newaliases . If /etc/aliases doesn't exist then create it first, then run newaliases .
Also maybe update/add alias_maps = hash:/etc/aliases to /etc/postfix/main.cf to get rid of the other warning.
Then try again.
(If you test with telnet, you don't need working DNS).

---

2nd issue: First remove $myhostname, $mydomain, from mydestination, since virtual domains shouldn't be listed here.
Then add (to main.cf):

virtual_mailbox_domains=dzervas.gr

Reload postfix and try again.