[Mimedefang] Previous relay information

[Damrose, Mark]

> -----Original Message-----
> From: Whit Blauvelt

> Alternately you could use $RelayAddr to recognize what's come 
> in by the secondary MX and segregate it somehow - assuming 
> that that system's not also sending you stuff as a normal 
> relay from the ISP or whatever - and then only go through 
> that file after an outage, figuring it's just collecting spam 
> otherwise.

There is no practical way to know of transient connection problems
between you and all potential senders at all times.  Just because your
"primary" is up and has an Internet connection doesn't mean it is
reachable from all hosts within their timeout.  If you have more than 1
MX, be prepared for *all* of them to be used.  Best practice is to apply
the same policy to all of them.

> I'm greylisting with an external secondary MX myself. Since 
> their line is more dependable than mine, it seems worth keeping. 

A secondary on a more dependable connection is a good thing, so long as
it is under your administrative control.