Milter-greylist

Le mercredi 24 avril 2019 � 22:22 +0200, John Damm S�rensen
john@... [milter-greylist] a �crit :
>   
> Provided that the members of the relay pool reside in the same subnet
> this statement is your savior:
> 
> subnetmatch /24

subnetmatch /16  or less /12 is better.

For example gmail has four MX CIDR:74.125.0.0/16
and one in CIDR:108.177.0.0/17

# dig +short MX gmail.com
20 alt2.gmail-smtp-in.l.google.com.
30 alt3.gmail-smtp-in.l.google.com.
40 alt4.gmail-smtp-in.l.google.com.
10 alt1.gmail-smtp-in.l.google.com.
5 gmail-smtp-in.l.google.com.
# dig +short alt1.gmail-smtp-in.l.google.com.
74.125.205.26
# dig +short alt2.gmail-smtp-in.l.google.com.
74.125.68.26
# dig +short alt3.gmail-smtp-in.l.google.com.
108.177.125.26
# dig +short alt4.gmail-smtp-in.l.google.com.
74.125.195.26
# dig +short gmail-smtp-in.l.google.com.
74.125.206.27

Another example

nasa.gov CIDR:198.120.0.0/14, 198.116.0.0/14
the 8 MX are inside  198.117.0.0/16

> 
> Best
> 
> John
> 
> 
> Den 24-04-2019 kl. 15:45 skrev Steve Rikli sr@...
> [milter-greylist]:
> 
> >   
> > I've been happily using milter-greylist for a few years, with pretty
> > great results -- spam level is barely noticeable, and I'm only using
> > greylist by itself at the moment.
> > 
> > Recently I've noticed again I'm occasionally missing messages, or at
> > least hitting multiple iterations of delays; when I dig into the
> > logs
> > it appears to result from the sender using a mail relay server
> > "pool".
> > 
> > E.g. the 1st delivery attempt comes from relay1.example.com, which
> > then
> > gets greylisted; the 2nd attempt comes from relay2.example.com, the
> > 3rd
> > from relay3, and so on.
> > 
> > In some cases a previous relay will get the message to try again,
> > and
> > the message will eventually be delivered normally.
> > 
> > In other situations, possibly with very large relay server pools
> > (?),
> > the autowhite timer for the relay(s) expires, and the sender
> > eventually
> > gives up presumably due to their own retry policies.
> > 
> > I've noticed this happening a few times with domains hosted by
> > office365
> > outlook.com, though I'd expect there are others.
> > 
> > When I notice these sort of issues, because it's a person or domain
> > I
> > want to associate with, I simply add them to my white list as
> > needed.
> > 
> > But I'm wondering if anyone has found a more automatic / elegant way
> > of handling situations like this.
> > 
> > Cheers,
> > sr.
> > 
> > 
> > 
> 
> 
> Virusfri. www.avast.com 
> 
> 
> 

-- 
Christian P�lissier
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