----- Original Message ----- > From: "Reindl Harald" <h.rei...@thelounge.net> > To: postfix-users@postfix.org > Sent: Sunday, 12 June, 2011 10:04:02 AM > Subject: Re: unverified_recipient_tempfail_action = permit > > > > Am 12.06.2011 09:06, schrieb Wiebe Cazemier: > >> so you do not need any backup-MX because if your primary > >> is not available the deferring happens on the sender > >> > >> this is the way smtp works > > > > Default defer time for most SMTP servers is only 3 to 5 days, that > > is not long enough for me. > > jokingly if you are longer than 3 times down with your primary MX > you should consider outsourving you mailservices!
Well, I also have some private servers and if I'm on vacation, I have a hard time fixing broken hardware. At this time, I have no cloud platform or other redundant platform in place. Plus, people sending me mail will get a defer notice. I'd rather prevent that. > > really - in the last ten years our longest outage of the mailserver > was 10 hours bcause a hardware-failure, so why does it bother > me how long is the defer time out there and if our server si longer > than 5 days down my smallest problem are a hand of mails bouncing > back to the sender > > >>> So if you would accept mail when the primary is down, you may > >>> very > >>> briefly > >>> create backscatter, but it allows you to operate a backup MX > >>> server > >>> without > >>> syncing recipient maps, or have any other knowledge about it > >> > >> nut the backup-mx is really useless if it depends on the primary > >> one > >> for > >> proper working and in the reality a backup-mx is useless, really > > > > I kind of disagree. It doesn't rely on the primary for proper > > functioning, > > it just makes use of knowledge of the primary when it can. > > IT DOES > > normally the backup-mx will get no messages as long as the primary is > available > so there are no valid/ivalid RCPT cached That is in a world where there is no spam. In a world where there is no spam, I don't need recipient address verification to reject mail on the backup to begin with. So when the primary is down, all is well. The only reason I do need recipient address verification is spam. And having the abused backup MX verify at the primary side, for me, is a good enough way to prevent backscatter. > > if your primary si down your backup-mx does know nothing and is a > backscatter > so cinfigure your mailservices properly or consider outsourcing them > to anybody > who can do this and makes a service level agreement where your mx is > not down > for some days I understand your point of view, but I think it should be possible to configure a MX server as backup for anyone who wants to use it, without maintaining extra address information, at the cost of creating backscatter when the primary is down (which can partly be avoided by installing good spam filtering).
