Hi guys. I'm facing with annoying behaviour with ISPConfig3 and email forwards.
Many customers set a forward from their mail account to external mail account.
I mean, user email@example.com
set to forward all the mails to firstname.lastname@example.org
All the spam mails received by email@example.com
are tagged with X-Spam flag and forwarded to firstname.lastname@example.org
These mails are received by yahoo mailserver but them seem to be generated by mail.myisp.com server IP address (as it is). Since these mails are spam, after a while Yahoo classifies our server as spammy and reject further email from us, blacklisting our server.
At this point, anyone of myisp.com domain are unable to send mail to yahoo.com, even if not spam.
Does anyone can point me in the right direction to avoid this behaviour? There is a way to allow only local address to be inserted in email forward list?