Ken wrote:
> We use spamd grey listing to combat spam.  Works great.  Gmail's mail
> servers pose a problem, however, in that they requeue mail from
> different mta's, resulting in subsequent delivery attempts coming from
> many different IP addresses, wh/eventually time out and get blacklisted.

My only successful workaround was to whitelist gmail. I have a text file
in /etc/mail containing the results of the following far-from-pretty command:

dig _spf.google.com TXT + short | tr "\ " "\n" | grep ip4: | cut -d: -f2 | sort 
-n

That gives me a concise list of the broad IP ranges that gmail uses for
outbound MTAs. Today, it looked like:

64.18.0.0/20
64.233.160.0/19
66.102.0.0/20
66.249.80.0/20
72.14.192.0/18
74.125.0.0/16
207.126.144.0/20
209.85.128.0/17
216.239.32.0/19

This list changes periodically. The first entry, for example, is not in
my current ruleset for gmail.

I then have the following rules in my pf.conf, just like what you need
to have for spamd to ever whitelist anyone:

table <gmail-white> persist file "/etc/mail/gmail.txt"

no rdr on $ext_if proto tcp from <gmail-white> to any port smtp

--Kyle

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