[TriLUG] mail filtering

[Rick DeNatale]

On 6/1/05, Jeffrey A. Groves <jgroves at krenim.org> wrote:
> I too have had mimedefang running for quite some time and have been very
> pleased with it.  I recently disabled the spamassassin portion as I was not
> getting any value-add on top of the multiple DNSBL that I use.

I hope that you are using that DNSBL as a filter rather than a block.

I was quite surprised to see how many false positives get generated by
DSNBLs. My isp blocks email which comes from any server which appears
on a variety of DSNBLs.  I was finding that this was doing things like
intermittently bouncing yahoo groups messages, and blocking certain
sourceforge and other mailing lists, including the initial sign-up
confirmation messages.  At the same time, spamassassin was finding
lots of spam which was slipping through this net.

I couldn't seem to convince the isp that blocking legitimate e-mail to
their customers was a bad thing, they were happy because it lowered
the load on their e-mail servers since they were throwing away so much
"spam."  In fact they were convinced that nothing but spam was getting
blocked, despite my persistent question of "how do you know?"

I ended up just going around them and setting up my own mail server
for my own domain which doesn't use DNSBLs except maybe to provide
input to spamassassin with a fairly low score.