Im confused by this situation. Two separate independent servers both running same version of postfix and both setup the same way with virtual users and alias address stored in SQL.
Okay, i think i figured out what is going on. On the second server that im sending email to, im sending from a third server that shares the same SQL tables as the second server. When i sent an email to the second server from an offsite service it behaved same as the first server acknowledging the alias.
I assume that the third server is looking up the alias address before sending the email to the second server and converting the alias to the realuser before the email goes out over the internet.
Is there anyway to prevent this behavior? Have the third server just send the email to who it was told to send it to, the alias address.
