I have a small SoHo network of machines and I have postfix installed on most of them for sending mail. The machines sit behind a NAT router which connects them to the internet, the domain name (as seen from the outside world) is zbmc.eu. All the machines are running xubuntu 10.04 and have postfix 2.7.0.
Within the LAN behind the router the machines have names like chris.zbmc.eu, mws.zbmc.eu, dps.zbmc.eu and so on. Most things are working OK, I can send and receive mail on my desktop machine OK via my ISP's smarthost and I get local messages OK. My problem has arisen on one of the machines which is a headless server, it's dps.zbmc.eu. I want E-Mail from that machine to be sent out via the mailhub machine on the network which is mws.zbmc.eu. The problem is that, whatever I try, the mailhub machine sees mail sent from dps.zbmc.eu as coming from zbmc.eu (well, its IP) and rejects it with a 'relaying denied' message. The bottom of /etc/postfix/main.cf on dps.zbmc.eu is:- myhostname = dps.zbmc.eu alias_maps = hash:/etc/aliases alias_database = hash:/etc/aliases myorigin = /etc/mailname mydestination = dps.zbmc.eu, localhost.zbmc.eu, localhost relayhost = mws.zbmc.eu mynetworks = 127.0.0.0/8 [::ffff:127.0.0.0]/104 [::1]/128 mailbox_command = procmail -a "$EXTENSION" mailbox_size_limit = 0 recipient_delimiter = + inet_interfaces = loopback-only inet_protocols = ipv4 What I see in /var/log/mail.log is:- Nov 16 16:04:20 mws postfix/smtpd[31242]: connect from unknown[84.45.228.40] Nov 16 16:04:20 mws postfix/smtpd[31242]: NOQUEUE: reject: RCPT from unknown[84.45.228.40]: 554 5.7. 1 <ch...@halon.org.uk>: Relay access denied; from=<ch...@dps.zbmc.eu> to=<ch...@halon.org.uk> proto=ESMTP helo=<dps.zbmc.eu> Nov 16 16:04:20 mws postfix/smtpd[31242]: disconnect from unknown[84.45.228.40] So why does postfix see the connection as if it comes from 84.45.228.40? It's as if it thinks the connection is from zbmc.eu as opposed to dps.zbmc.eu but everything is set to say I'm sending from dps.zbmc.eu. The command 'host dps.zbmc.eu' returns 'dps.zbmc.eu has address 192.168.1.2' on both dps.zbmc.eu and on mws.zbmc.eu. (Oh, /etc/mailname contains dps.zbmc.eu too) Any help or suggestions would be most welcome, I can supply more information if needed. A rejected message is as follows:- Date: Tue, 16 Nov 2010 16:02:54 +0000 (GMT) From MAILER-DAEMON Tue Nov 16 16: 2:54 2010 From: Mail Delivery System <mailer-dae...@dps.zbmc.eu> To: ch...@dps.zbmc.eu Subject: Undelivered Mail Returned to Sender [-- Attachment #1: Notification --] [-- Type: text/plain, Encoding: 7bit, Size: 0.5K --] This is the mail system at host dps.zbmc.eu. I'm sorry to have to inform you that your message could not be delivered to one or more recipients. It's attached below. For further assistance, please send mail to postmaster. If you do so, please include this problem report. You can delete your own text from the attached returned message. The mail system <ch...@halon.org.uk>: host zbmc.eu[84.45.228.40] said: 554 5.7.1 <ch...@halon.org.uk>: Relay access denied (in reply to RCPT TO command) [-- Attachment #2: Delivery report --] [-- Type: message/delivery-status, Encoding: 7bit, Size: 0.3K --] Reporting-MTA: dns; dps.zbmc.eu X-Postfix-Queue-ID: E83EE100283 X-Postfix-Sender: rfc822; ch...@dps.zbmc.eu Arrival-Date: Tue, 16 Nov 2010 16:02:53 +0000 (GMT) Final-Recipient: rfc822; ch...@halon.org.uk Action: failed Status: 5.7.1 Remote-MTA: dns; zbmc.eu Diagnostic-Code: smtp; 554 5.7.1 <ch...@halon.org.uk>: Relay access denied [-- Attachment #3: Undelivered Message --] [-- Type: message/rfc822, Encoding: 7bit, Size: 0.5K --] Return-Path: <ch...@dps.zbmc.eu> Received: by dps.zbmc.eu (Postfix, from userid 1000) id E83EE100283; Tue, 16 Nov 2010 16:02:53 +0000 (GMT) Date: Tue, 16 Nov 2010 16:02:53 +0000 From: Chris Green <ch...@dps.zbmc.eu> To: ch...@halon.org.uk Subject: Test message Message-ID: <20101116160253.ga1...@dps.zbmc.eu> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.5.20 (2009-06-14) This is a test -- Chris Green (at server dps) -- Chris Green