blackmail attempt? Stable mailing list block?

[Matthew Dillon]

    I'm going to put a plug in for the relays.ordb.org DNSBL.  It's a
    fairly conservative volunteer dnsbl that verifies and blocks open
    relays in an automated fashion.  I run one of their U.S. nameservers.

    I consider DNSBLs only one line of defense.  I have a number of 
    mechanisms in my own mail system which detect suspect connections
    through the libmilter interface and track and return 4xx codes for a
    period of time to 'delay' (rather then reject) suspect email for a few
    hours.  I can't really do anything drastic because I run the email and
    domains for several dozen people and some of them get all sorts of
    weirdly sourced, legitimate international correspondance.

    Even so three or four out of the 30-40 spams that attempt delivery to
    my personal email address every day get through.  I am still hesitating on
    implementing the final solution, which would be a mail-back verification
    system, but if spam continues to worsten over this year I'll probably
    wind up implementing it.

    There are plenty of things that people can do to mitigate spam.  For one
    thing, never publish your email address in user at domain form on your web
    pages.  Instead publish it as 'user at domain' or something like that.
    That one change will probably get rid of a significant percentage of the
    spam you get.  I've started doing it on my web pages and I'll probably
    do it for my email signature as well since those are archived and available
    on the web as well.

    Another interesting and cool solution, one which I might implement for
    myself, is to create 'temporary return addresses' for your email and/or
    published web pages which are only valid for a short period of time.

					-Matt
					Matthew Dillon 
					<dillon at backplane.com>


:
:We don't use 'monkies.org' because they refuse to take fixed computers out.  we send an email to spews and dk10? telling them that they MISSED one of our netblocks and please add it since we didn't want to send any email to anyone stupid enough to use either list. (they added it, which proved my point.. they violated their stated listing policies!)
:
:here is what I use (in postfix)
:we don't do any business out of the us, so screwem.
:...
:
:-- 
:Michael  S. Scheidell, CEO
:SECNAP Network Security www.secnap.com
:scheidell at secnap.net  / 1+561.368.9561, 1131
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