In 20 years never saw need for backup mx. If MX pool is down remote MTA should queue it.
Only practical use I've seen is NoListing setup. I suppose you might run a server in the Arctic which could lose contact for weeks and you'd want to ensure no bounces. Ymmv. Sent from my iPhone > On May 25, 2016, at 08:18, "sha...@shanew.net" <sha...@shanew.net> wrote: > >> On Wed, 25 May 2016, Dianne Skoll wrote: >> >> On Wed, 25 May 2016 13:05:57 +0200 >> Support SimpleRezo <simpler...@gmail.com> wrote: >> >>> We are expecting a problem when emails are coming from our MX2 with >>> the SPF plugin, because the SPF test is made on the last "Received" >>> IP and not the first one (as we can expect for a SPF test). >> >>> Does someone has already notice this? Can this be fixed by >>> configuration? >> >> Yes. Don't run a backup MX machine that relays to a primary machine >> that does spam-scanning. It's more trouble than it's worth, particularly >> as spammers sometimes specifically pick the worst MX record rather than >> the best. > > It also seems problematic for your backup MX to accept an email only > for your primary to potentially reject said email later on. At that > point you can no longer reject the mail, leaving the problematic (some > might say wrong) choices to either bounce it or drop it (or deliver > it, I suppose, if you're only using SA to provide info to end users). > > Running the same SA setup on your backup would seem to minimize that > risk, but not totally eliminate it, since network-based tests might > return different results given sufficient time until your backup > finally transfers to the primary. > > So, for those with more experience, what is the preferred way to run a > backup MX (or two or three, etc.) without losing or breaking the > benefit of spam filtering? > > -- > Public key #7BBC68D9 at | Shane Williams > http://pgp.mit.edu/ | System Admin - UT CompSci > =----------------------------------+------------------------------- > All syllogisms contain three lines | sha...@shanew.net > Therefore this is not a syllogism | www.ischool.utexas.edu/~shanew
