postfix internal mail forward fails

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#1 Tue, 12/20/2011 - 10:49

postfix internal mail forward fails

hi there

i recently changed the hostname of the system. everything runs fine, mail sending and receiving works but mail forwards.

for example:

userA has his mail forwarded to userB (both on the same domain), both have regular mail accounts (no alias, just forward copy)

if i send mail to userA, the mail is properly transfered to the inbox but not forwarded to userB, instead i receive as a sender: (expanded from unknown user: "userB" ...

Action: failed Status: 5.1.1 Diagnostic-Code: X-Postfix; unknown user: "userB"

Both accounts are working otherwise. I can send mail to both, but copy-forwarding is not possible. This is a major problem as it's often used if someone from the office is having vacation and his mail has to be checked. Furthermore the error is sent out to the sender which leaves the impression, the mail was not delivered, it was but not forwarded internally. forwards to external adresses are working.

i have basically no idea, as it looks more like a bug somewhere because everything else is working.

any tip would be really welcome m

Tue, 12/20/2011 - 12:16


If you go into System Settings -> Re-Check Config, does it see any problems with the setup there?


Tue, 12/20/2011 - 12:23

everything tells it's nice.

i made a test:

if i forward the mail to userB.domain@localhost

the mail is delivered, would be a workaround, but rather ugly to handle for endusers

i think i has something to do how postfix handles internal mail, strange is that mail from to are working, but no forwards, haven't checked alias yet.

best m

Tue, 12/20/2011 - 12:47

i changed the following:

in my mails it was always mentioned that sender is and not, which resulted into problems with rdns, my ip at is set to resolve:

in virtualmin i changed:

webmin -> networking -> networking configuration -> hostname and dns -> hostname servers -> postfix -> general options -> What domains to receive mail for

because changing the hostname was not changing postfix entry

and additionaly via shell: /etc/postfix/ -> myhostname

because it was not changed by webmin as well

i changed these settings according to some suggestions in the forum. mail works no like i want it beside the internal forwards.

hope this hint helps for a solution best m

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