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I've googled for quite a while now and can't find a good explanation for the following issue.

I receive the following error when trieing to send a mail to user@server.example.de

Jul 23 15:24:30 vslpam10 postfix/smtpd[7970]: connect from relay.subdomain.example.de[<IP>]
Jul 23 15:24:30 vslpam10 postfix/smtpd[7970]: B08A1C4B0: client=relay.subdomain.example.de[<IP>]
Jul 23 15:24:30 vslpam10 postfix/cleanup[7973]: B08A1C4B0: message-id=<645638F41810994799AADD85BDB1C38F65866EEE@somedomain.example.de>
Jul 23 15:24:30 vslpam10 postfix/smtpd[7970]: disconnect from relay.subdomain.example.de[<IP>]
Jul 23 15:24:30 vslpam10 postfix/qmgr[7943]: B08A1C4B0: from=<sender@example.de>, size=14053, nrcpt=1 (queue active)
Jul 23 15:24:30 vslpam10 postfix/smtp[7974]: B08A1C4B0: to=<user@server.example.de>, relay=relay.subdomain.example.de[<IP>]:25, delay=0.06, delays=0.03/0.01/0/0.02, dsn=5.1.1, status=bounced (host relay.subdomain.example.de[<IP>] said: 550 5.1.1 <user@server.example.de>: Recipient address rejected: User unknown in local recipient table (in reply to RCPT TO command))
Jul 23 15:24:30 vslpam10 postfix/cleanup[7973]: BE364C55B: message-id=<20120723132430.BE364C55B@server.example.de>
Jul 23 15:24:30 vslpam10 postfix/bounce[7976]: B08A1C4B0: sender non-delivery notification: BE364C55B
Jul 23 15:24:30 vslpam10 postfix/qmgr[7943]: BE364C55B: from=<>, size=16447, nrcpt=1 (queue active)
Jul 23 15:24:30 vslpam10 postfix/qmgr[7943]: B08A1C4B0: removed
Jul 23 15:24:30 vslpam10 postfix/smtp[7974]: BE364C55B: to=<sender@example.de>, relay=relay.subdomain.example.de[<IP>]:25, delay=0.02, delays=0/0/0/0.01, dsn=2.0.0, status=sent (250 2.0.0 Ok: queued as C124512C5D4)
Jul 23 15:24:30 vslpam10 postfix/qmgr[7943]: BE364C55B: removed

The User does exist however:

finger user
Login: user                          Name: technical User

Postconf shows the following

(postconf -d; postconf -d; postconf -n; ) | sort | uniq -u
alias_maps = hash:/etc/aliases                                                                                                                            allow_mail_to_commands = alias,forward,include
allow_mail_to_files = alias,forward,include
biff = no
canonical_maps = hash:/etc/postfix/canonical
daemon_directory = /usr/lib/postfix
html_directory = /usr/share/doc/packages/postfix/html
inet_protocols = all
local_recipient_maps = unix:passwd.byname $alias_maps
mailbox_size_limit = 0
manpage_directory = /usr/share/man
masquerade_exceptions = root
myhostname = server.example.de
mynetworks = <IPs>
readme_directory = /usr/share/doc/packages/postfix/README_FILES
relocated_maps = hash:/etc/postfix/relocated
sample_directory = /usr/share/doc/packages/postfix/samples
sender_canonical_maps = hash:/etc/postfix/sender_canonical
setgid_group = maildrop
smtpd_sender_restrictions = hash:/etc/postfix/access
transport_maps = hash:/etc/postfix/transport
virtual_alias_domains = hash:/etc/postfix/virtual
virtual_alias_maps = hash:/etc/postfix/virtual

Has anybody got an explanation for this behaviour?

Best regards

share|improve this question
Why on earth are you setting so many (useless) default values in main.cf? Please provide the output of (postconf -d; postconf -d; postconf -n; ) | sort | uniq -u so we can see what you really did. –  adaptr Jul 23 '12 at 13:59
Thanks for the info. –  Guardian Jul 23 '12 at 14:08
And now the real, complete log from the rejection, please :) –  adaptr Jul 23 '12 at 14:09
And done also ;-). –  Guardian Jul 23 '12 at 14:18
Just to be sure, the user exists on relay.subdomain.example.de since that is where the mail is getting delivered to? –  becomingwisest Jul 23 '12 at 14:40

1 Answer 1

up vote 3 down vote accepted

If postfix is configured to accept mail for a specific destination (as set in mydestination), there must also exist a valid alias or mailbox entry for that user.

Instead, you wish to relay this mail to another system - so the user does not exist.

There are two solutions to this, a bad one and a good one.

The bad solution is simple to implement: switch relay.example.com to relay_domains, and make sure relay_recipient_maps is set to empty:

relay_domains = relay.example.com
relay_recipient_maps = 

This means that all recipients for relay.example.com will be accepted, so you will receive plenty of spam.

The right way to do this is to set relay_recipient_maps to a list of valid addresses in the relay domain.

EDIT: drat, I forgot that you said the user does exist.

In that case, here is what happens: you have not added the relay. subdomain to mydestination, and mydestination (and ONLY mydestination) does not obey parent_domain_matches_subdomains, specifically.

So you could solve it by adding the relay. subdomain to mydestination explicitly, assuming the relay. domain is transported(5) away before being locally delivered.

share|improve this answer
Works like a charm. Thank you very much! –  Guardian Jul 24 '12 at 11:30

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