Postfix: Relay mails from specific domain

Question

I'm using postfix in combination with Zarafa as Groupware (local server) and import mails from an external server to a mailbox on my local server. I do this, because of restricted resources on the external server.

So incoming mails at the external server are redirected to my local server - but sending mails is done on the local server. The problem is, that the rx-Record of the domain of the external mail server does not point to my server - so my send mails are marked as spam, especially in GMail.

Therefore I want to relay the outgoing mails of the local mailbox to the external server to fix this issue. I want to restrict this relaying to this single domain - there are other domains on the local server witch don't need to be relayed, because the domains are owned by me and the MX record is correct.

Calista

can you post the output of postconf -n to help you better. – Sclerodermatous

Answer 1

Got it to work with relay server:

main.cf

sender_dependent_relayhost_maps = hash:/etc/postfix/relaymaps
smtp_sender_dependent_authentication = yes
smtp_sasl_auth_enable = yes
smtp_sasl_password_maps = hash:/etc/postfix/sasl_passwd
smtp_sasl_type = cyrus
smtp_sasl_security_options = noanonymous

... and creating relaymaps and sasl_passwd file

Calista