Hi, I'm working on a mail server deployment that will only have one server for MX and SASL submission purposes. Generally I like to have separate Postfix instances to handle a specific task. In this case I'm running in to problems when the submission instance uses the same IP address as the MX instance. (Due to a limited IP address pool there is currently only one routable IP address assigned to this server.)
Using the submission instance to send a message to a recipient address for which the server is also the MX host triggers Postfix' loop detection. Mail for foreign addresses is relayed correctly. I realize this can be done easily enough without using multiple instances. Is there a way to work around this so that an MX instance and submission instance can share single IP address? I've gotten used to the queue, logging, and configuration separation provided by multiple instances and would rather like to use that approach here if I can. Configuration and debugging information follow. In this example, the server is the MX host for both domains 'example.com' and 'example.org'. m...@mail[~]$ nc 127.0.0.1 587 220 smtp.example.com ESMTP Postfix EHLO test 250-smtp.example.com 250-PIPELINING 250-SIZE 10240000 250-VRFY 250-ETRN 250-AUTH PLAIN LOGIN 250-ENHANCEDSTATUSCODES 250-8BITMIME 250 DSN AUTH PLAIN blahblahblah 235 2.7.0 Authentication successful MAIL FROM:<m...@example.com> 250 2.1.0 Ok RCPT TO:<m...@example.org> 250 2.1.5 Ok DATA 354 End data with <CR><LF>.<CR><LF> test . 250 2.0.0 Ok: queued as 098981BF0969 quit 221 2.0.0 Bye Corresponding log entries for above transaction: Jul 31 18:27:48 mail postfix-submission/smtpd[13440]: connect from localhost.localdomain[127.0.0.1] Jul 31 18:27:56 mail postfix-submission/smtpd[13440]: 098981BF0969: client=localhost.localdomain[127.0.0.1], sasl_method=PLAIN, sasl_username=m...@example.com Jul 31 18:27:59 mail postfix-submission/cleanup[13442]: 098981BF0969: message-id=<20100801012756.098981bf0...@smtp.example.com> Jul 31 18:27:59 mail postfix-submission/qmgr[13433]: 098981BF0969: from=<m...@example.com>, size=348, nrcpt=1 (queue active) Jul 31 18:27:59 mail postfix-submission/smtp[13443]: 098981BF0969: to=<m...@example.org>, relay=none, delay=4.7, delays=4.6/0.09/0/0, dsn=5.4.6, status=bounced (mail for example.org loops back to myself) Jul 31 18:27:59 mail postfix-submission/cleanup[13442]: AB7021BF096B: message-id=<20100801012759.ab7021bf0...@smtp.example.com> Jul 31 18:27:59 mail postfix-submission/qmgr[13433]: AB7021BF096B: from=<>, size=2151, nrcpt=1 (queue active) Jul 31 18:27:59 mail postfix-submission/bounce[13445]: 098981BF0969: sender non-delivery notification: AB7021BF096B Jul 31 18:27:59 mail postfix-submission/qmgr[13433]: 098981BF0969: removed Jul 31 18:27:59 mail postfix-submission/smtp[13443]: AB7021BF096B: to=<m...@example.com>, relay=none, delay=0.15, delays=0.15/0/0/0, dsn=5.4.6, status=bounced (mail for example.com loops back to myself) Jul 31 18:27:59 mail postfix-submission/qmgr[13433]: AB7021BF096B: removed Jul 31 18:28:02 mail postfix-submission/smtpd[13440]: disconnect from localhost.localdomain[127.0.0.1] postconf -c /etc/postfix-submission -n: alias_database = alias_maps = config_directory = /etc/postfix-submission data_directory = /var/lib/postfix-submission default_database_type = cdb local_recipient_maps = local_transport = error:5.1.1 Mailbox unavailable multi_instance_enable = yes multi_instance_name = postfix-submission mydestination = mydomain = example.com myhostname = smtp.example.com myorigin = $mydomain parent_domain_matches_subdomains = queue_directory = /var/spool/postfix-submission smtpd_client_restrictions = permit_sasl_authenticated reject smtpd_helo_required = yes smtpd_recipient_restrictions = reject_non_fqdn_recipient permit_sasl_authenticated reject smtpd_sasl_auth_enable = yes smtpd_sasl_path = /var/run/dovecot/auth-client smtpd_sasl_security_options = noanonymous smtpd_sasl_type = dovecot smtpd_sender_restrictions = reject_non_fqdn_sender reject_unknown_sender_domain strict_rfc821_envelopes = yes unknown_address_reject_code = 554 unknown_client_reject_code = 554 unknown_hostname_reject_code = 554 mail_version = 2.8-20100707 In master.cf for the postfix-submission instance, the "smtp inet ... smtpd" entry is commented out, and "submission inet ... smtpd" is enabled. Thanks, Mike
