[Mimedefang] Re: Great open letter about anti-virus, emails, bounces, etc.

[Matt Cramer]

On Mon, 15 Sep 2003, Michael Sims wrote:

> I'm curious, since I would love to put something like this into place.  (It
> seems that here lately the amount of spam from dial-up/dynamic accounts has
> skyrocketed).  In the examples you give (outsourced mail, and relays without
> PTR records), how did you know about the problem?  I mean, if you're
> rejecting mail on this basis, how did you know that some of it was legit?
> Did someone contact you through some other means?

Old tech: telephone.  Person tries to send to us, it gets rejected,
then they call our luser who calls our HellDesk who complains they can't
get mail from person.  I check my logs and see why, then add an
exception after talking to person'a admin.  Crude, but effective.

> I'm seriously considering setting up a blacklist like this where I can tell
> relays with PTR records like...
>
> /ip.*\.suscom\.net/
> /pcp.*\.comcast\.net/
> /.*ppp.*\.tiscali\.no/
> /([0-9]{1,3}-){3}[0-9]{1,3}\..*\.rr.com/
> /([0-9]{1,3}-){3}[0-9]{1,3}\.client\.insightBB\.com/
> /([0-9]{1,3}-){3}[0-9]{1,3}\.client\.attbi\.com/

I understand why people do this (BTW there are RBLs of dynamic ranges so
you can let someone else do the work for you and just use mimedefang to
check the RBL) but it drives me nuts, because I run my personal domain off
of my [dynamic] DSL line.  People can accept mail from whomever they
choose, of course, but I am confident that *MY* mail server is as good if
not better configured than the average ISP's.  If I send all my mail
through the ISP's mail server, then I have to deal with their brain-dead
configs, dropping mail, carnivore ;) etc. etc.

However as more people decide to block dynamic IPs though I suppose I'll
have to set up a smart relay somewhere....maybe at work.  :)


Matt

-- 
Matthew S. Cramer <mscramer at armstrong.com>          Office: 717-396-5032
Infrastructure Security Analyst                     Fax:    717-396-5590
Armstrong World Industries, Inc.                    Cell:   717-917-7099