Re: Help with SPAM blocking

[Sebastian Reitenbach <sebastia () defiant deep-space.ds9>]

Hi dan,

maybe you consider greylisting to fight spam and many self sending mail 
viruses.
http://www.greylisting.org
openbsd includes a spamd which does this greylisting thing in combination with 
the firewall. it is transparently integratable into a mail setup.
http://www.openbsd.org/cgi-bin/man.cgi?query=spamd&apropos=0&sektion=0&manpath=OpenBSD+Current&arch=i386&format=html

but there are also other greylisting plugins for sendmail, postfix and 
others...



cheers
buzz

Am Mittwoch, 19. Januar 2005 19:38 schrieb Dan Lynch:
> Greetings list,
>
> I'm new to SPAM blocking and am trying to ramp up my knowledge of its
> mechanisms. I've done several days of research all over the net and
> there are still some points of confusion I can't seem to find
> explanations for. Anything you can help clarify for me is most
> appreciated. I also welcome reference to more focused mail lists I can
> query.
>
> First, I'm still looking for a good technical explanation of how
> Realtime Blackhole Lists (RBLs) work. Many references have specific
> implementation details (the syntax of the sendmail config lines, etc),
> but not the overview of RBL technology. The overviews I have found are
> too generic and mail-recipient/end-user oriented to be of much use.
>
> Do RBL's have a standard file format? What's it look like?
>
> What I can glean from FAQs and documentation implies there are two
> types: SMTP based and DNS based. Is this correct? Or is DNSRBL
> synonymous with RBL? Some lists (like njabl.org) imply they can be used
> by a DNS server, but I'm not clear how that functions. Why do so many
> references mention loopback addresses (see www.njabl.org/use.html, or
> the declude.com database). What's the connection?
>
> Is it best practice to use one list integrated with your DNS server, or
> saved as a hosts file on your mail server, and another configured at
> your SMTP gateway?
>
> Also, is an RBL downloaded to your SMTP host, or is it used as a remote
> query? If it's remote, how can one create exceptions when needed? Is
> that where your SMTP gateway's white-list feature comes in?
>
> Again, thanks for any info you can provide.
>
> Dan Lynch, CISSP
> County of Placer
> Auburn, CA
>
> dlynch at placer dot ca dot gov