Hi Noel, thank you for your reply. You know, in real world, ips/ranges get blocked from time to time and i would like to be ready for this and not rely on others :) The workaround looks indeed crappy - i wonder how others handle this situation in "bigger" setups? I'm currently having 7000-8000 mails / day.
Stefan Am Fr., 31. Mai 2019 um 18:37 Uhr schrieb Noel Jones <njo...@megan.vbhcs.org >: > On 5/31/2019 1:48 AM, Stefan Bauer wrote: > > Hi, > > > > I'm running a pair of postfix-servers in different data-centers > > (different ip networks) for outgoing-only delivery. once in a while > > my providers /22 appear on public blacklists, so mails from my nodes > > also gets rejected. > > > > For this, i have now a third backup-instance in another data center > > that is not visible to my users and only fairly with dummy mails > > used to keep reputation up and good. Howto re-route traffic on > > demand with postfix in case, ip-networks get blocked again? > > > > How do others handle this? > > > > Thank you. > > > > Stefan > > > Much better to send all your mail via the ISP that doesn't get their > whole space blocked, rather than a crappy workaround. > > For a crappy workaround, you can use smtp_reply_filter to turn 5xx > rejects due to blacklists into 4xx temp failures, then use > smtp_fallback_relay to send the temp failures to your backup server. > This will send other mail to the backup server, such as greylisted > mail or mail that temp fails for unrelated reasons. Try to make your > reply filter narrow enough that it doesn't transform rejects for > non-rbl reasons, such as unknown recipient. > > http://www.postfix.org/postconf.5.html#smtp_reply_filter > http://www.postfix.org/postconf.5.html#smtp_fallback_relay > > > > -- Noel Jones >
