[TriLUG] recent "Poor Reputation Sender" bounces

[Wes Garrison via TriLUG]

In my limited experience with exim4 and email servers, the "new normal" as
of about 3 years ago is that you  need 2 essential things to ensure
deliverability:
1) valid reverse DNS (aka PTR record) which has been discussed.
2) email signed with DKIM signature.

In addition, most places want a valid SPF record in DNS.

HP started blocking emails to their "e-printers" without warning a few
years ago due to no DKIM signature.

DKIM is pretty easy to set up on Debian/*buntu and requires a private key
on pilot and a public key stored in the DNS for each host that will be
sending email.

-Wes