Attempt MX, fallback to relay in case of error only
Is there a way to configure postfix to use a relay only if direct delivery is rejected? The case being a web application that has to send notification to subscribers, but some servers reject the connection (app IP originates from AWS EC2). I want those cases to be retried using a paid SMTP relay like authsmtp.com. However I don't want to use the relay for everything since it costs per mail. Thanks, ~ Remus
Attempt MX, fallback to relay in case of error only
cont...@rusanu.com put forth on 11/18/2009 10:05 AM: > Thanks Andreas, > > The reject would be '553 Mail from ... not allowed', so it sounds like a > dead end trying to configure postfix to handle this. > Suggestions on how to workaround are welcome. Given that the Amazon cloud is likely universally smtp blocked and will continue to be in the foreseeable future, you're probably not going to be able to work around this rejection problem by tweaking how postfix delivers mail. I blocked the Amazon cloud /18 in April, and sometime around late summer (US) a thread ran through the spam-l list causing universal blocking via the members. I'm sure the list of sites blocking it has only grown since then. Your best solution is to find a relayhost with good reputation from which you can send the email, one that doesn't cost you an arm and a leg to do so. Or, better yet, ditch the Amazon cloud and sign up with a decent colo/vps/web hosting shop whose IP space isn't universally smtp blocked. There are thousands of such providers out there offering ultra cheap service. Do some research and pick one whose IP space isn't in scorched earth territory. -- Stan
Re: Attempt MX, fallback to relay in case of error only
On Tue, 2009-11-17 at 20:55 -0800, cont...@rusanu.com wrote: > Is there a way to configure postfix to use a relay only if direct > delivery is rejected? The case being a web application that has to > send notification to subscribers, but some servers reject the > connection (app IP originates from AWS EC2). I want those cases to be > retried using a paid SMTP relay like authsmtp.com. However I don't > want to use the relay for everything since it costs per mail. > > Thanks, > ~ Remus I think you need a fallback_relay http://www.postfix.org/postconf.5.html#fallback_relay
Re: Attempt MX, fallback to relay in case of error only
Zitat von "cont...@rusanu.com" : Is there a way to configure postfix to use a relay only if direct delivery is rejected? The case being a web application that has to send notification to subscribers, but some servers reject the connection (app IP originates from AWS EC2). I want those cases to be retried using a paid SMTP relay like authsmtp.com. However I don't want to use the relay for everything since it costs per mail. If it is rejected with a permanent error code (5xx) no retry an no fallback will happen. This is required by RFC. If the reject is with some temporary reject code or the connection is not accepted at all you need the fallback_relay parameter. Regards Andreas
Re: Attempt MX, fallback to relay in case of error only
Thanks Andreas, The reject would be '553 Mail from ... not allowed', so it sounds like a dead end trying to configure postfix to handle this. Suggestions on how to workaround are welcome. Thanks, ~ Remus On Nov 18, 2009, at 1:12 AM, lst_ho...@kwsoft.de wrote: Zitat von "cont...@rusanu.com" : Is there a way to configure postfix to use a relay only if direct delivery is rejected? The case being a web application that has to send notification to subscribers, but some servers reject the connection (app IP originates from AWS EC2). I want those cases to be retried using a paid SMTP relay like authsmtp.com. However I don't want to use the relay for everything since it costs per mail. If it is rejected with a permanent error code (5xx) no retry an no fallback will happen. This is required by RFC. If the reject is with some temporary reject code or the connection is not accepted at all you need the fallback_relay parameter. Regards Andreas
Re: Attempt MX, fallback to relay in case of error only
cont...@rusanu.com: > Thanks Andreas, > > The reject would be '553 Mail from ... not allowed', so it sounds like > a dead end trying to configure postfix to handle this. > Suggestions on how to workaround are welcome. This is essentially the same problem as home office sites trying to send direct mail from a residential pool with fall-back to some ISP because their address is listed in zen.spamhaus.org. /etc/postfix/main.cf: smtp_fallback_relay=mail.isp.net /etc/postfix/master.cf: smtp unix - - n - - smtp -o soft_bounce=yes When the direct-to-destination delivery attempt fails, it will be the same Postfix SMTP client process that dumps the message to the fallback host, so 5xx replies will be ignored in both cases, and mail may remain queued forever. Ignoring 5xx responses is not kosher use of SMTP, and there is no enthousiastic support for Postfix to give 5xx replies a treatment that depends on context. Wietse > Thanks, > ~ Remus > > On Nov 18, 2009, at 1:12 AM, lst_ho...@kwsoft.de wrote: > > > Zitat von "cont...@rusanu.com" : > > > >> Is there a way to configure postfix to use a relay only if direct > >> delivery is rejected? The case being a web application that has to > >> send notification to subscribers, but some servers reject the > >> connection (app IP originates from AWS EC2). I want those cases to > >> be retried using a paid SMTP relay like authsmtp.com. However I > >> don't want to use the relay for everything since it costs per mail. > > > > If it is rejected with a permanent error code (5xx) no retry an no > > fallback will happen. This is required by RFC. > > If the reject is with some temporary reject code or the connection > > is not accepted at all you need the fallback_relay parameter. > > > > Regards > > > > Andreas > > > > > > >
