DNS BlackLists

[Richard Siddall]

Kelly Hamlin wrote:
>
> Does anyone know of any more DNS Blacklists i can add? Aside from what i
> listed here is whats in my sendmail.cf. I added the spamcop.net one
> thismorning, and this drastically cut down on the number of spam.
>

There's a reasonably comprehensive list at ORDB.  Do a database lookup and then
click on "Look up this host in non-ORDB RBL's," for example:
http://www.ordb.org/lookup/rbls/?host=pegasus.cyberstreet.com

UXN Spam Combat (http://combat.uxn.com) also has "Mønsted's DNSBL Check," which
is a link to: http://moensted.dk/spam/

Also, OSIRUSOFT provides a lookup on other DNSBLs it knows about at
http://relays.osirusoft.com/, for example:
http://relays.osirusoft.com/cgi-bin/rbcheck.cgi?addr=204.117.207.7

There's a link on the bottom of the Osirusoft page to:
http://www.sdsc.edu/~jeff/spam/cbc.html which actually does a comparison of some
DNSBLs.

The point I should be making is that there are plenty of DNSBLs you could add.
It would result in you rejecting mail from everyone.  Don't use a DNSBL you don't
trust.

We're currently using ORDB (relays.ordb.org), Spamhaus (sbl.spamhaus.org), and
Spews (spews.relays.osirusoft.com).  Spews is a little overzealous and keeps
blocking Topica.

Oh, I found sendmail dropped and added spaces in the reject message unless I put
quotes around fixed text, e.g.:
R<?>$+                  $#error $@ 5.7.1 $: "550 Mail from " $&{client_name} " rejected - see http://ordb.org/lookup/"

(Unfortunately the database search for most of the DNSBLs doesn't seem to handle
the client name or client address format sendmail generates, so you can't generate
useful URLs for the poor sysadmin who has to deal with your reject.)

Regards,

        Richard Siddall