On 11/9/2011 6:19 AM, Christian Vieser wrote: > Hi, > > we have a two ISP setup and each ISP provides us with an mail relay > accessible within their networks. > So we have in our postfix configurations > relayhost = [relaying.ISP1.com] > smtp_fallback_relay = [relaying.ISP2.com] > to provide some fault tolerance. This works pretty good in case we > have problems with one of our ISPs. > > Yesterday ISP1 changed the IP address of his relay. Therefore the > routing rules on the firewall didn't match any more and the packets > went down the wrong way. Consequently they were rejected by the relay: > > Nov 9 08:56:03 mailhost postfix/pickup[14967]: 4D0373A2C7: uid=104 > from=<XY> > Nov 9 08:56:03 mailhost postfix/cleanup[15247]: 4D0373A2C7: > message-id=<20111109075603.4D0373A2C7@mailhost> > Nov 9 08:56:03 mailhost postfix/qmgr[1496]: 4D0373A2C7: > from=<x...@opti-serv.de>, size=1072, nrcpt=1 (queue active) > Nov 9 08:56:03 mailhost postfix/smtp[15249]: 4D0373A2C7: > to=<x...@opti-serv.de>, orig_to=<XYZ>, > relay=relaying.ISP1.com[aa.bbb.ccc.ddd]:25, delay=0.14, > delays=0.03/0.01/0.07/0.03, dsn=5.7.1, status=bounced (host > relaying.ISP1.com[aa.bbb.ccc.ddd] said: 554 5.7.1 > <x...@opti-serv.de>: Relay access denied (in reply to RCPT TO command)) > Nov 9 08:56:03 mailhost postfix/bounce[15250]: 4D0373A2C7: sender > non-delivery notification: 70A193A2C8 > Nov 9 08:56:03 mailhost postfix/qmgr[1496]: 4D0373A2C7: removed > > So, first question is: why doesn't postfix try to deliver the mails > through the fallback relay?
The smtp_fallback_relay is used when relayhost cannot be reached. In this case, a server was contacted at the relayhost IP, and that server rejected the mail. http://www.postfix.org/postconf.5.html#smtp_fallback_relay > Second question: Even if I had no fallback relay defined, I wouldn't > like the mails to be discarded as happened here. The mail was not discarded, rather it was returned to the sender. > Is there a way I > can instruct postfix to keep the mails in his queue (at least to > maximal_queue_lifetime ), so that they can be delivered when the > problem is solved? You might add "-o soft_bounce=yes" to the master.cf smtp...smtp transport entry (NOT in main.cf). Be aware that setting soft_bounce can cause other problems and is not recommended other than for testing. http://www.postfix.org/postconf.5.html#soft_bounce -- Noel Jones
