Arrogant RBL list maintainers

Michael Holstein michael.holstein at
Wed Dec 9 14:53:10 CST 2009

> All of the DNSBLs I know are about outbound mail hosts, not inbound
> ones.  What are your sending hosts called?

Outbound goes through the same 4 boxes. We used to split it up (2 at
MX10, 2 at MX20 .. reversed for outbound) but for capital
(licensing/hardware) reasons we decided to do in/out through the same
system. This is just "first touch" on the way in and "last touch" on the
way out.

We also have spfv1 records defined (albeit a rather permissive "ptr
~all") .. but as I mentioned, the firewall disallows smtp to anywhere
but appropriate hosts. We do still allow smtps and submission to
accommodate folks that travel, as we haven't (yet) had a problem with
bots using either of those services.

My beef with Trend was that they were in essence telling us to re-do DNS
on our /16 because they didn't like the way we did it .. despite the
mail part (the one that matters) being technically correct by most
everyone else's standards. Personally, I think this is just so they can
have a "big list" when they sell it (.. our DNSBL has $x million more
entries than $competitor..).


Michael Holstein
Cleveland State University

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