[NTLUG:Discuss] How does MAPS RBL work?

[Carl Haddick]

I have a question about DNS mechanisms.

On Wed, Jul 02, 2003 at 04:33:18PM -0700, joseph beasley wrote:
> The queries are direct to their dns server.  If you are using sendmail,
> there are options for RBL servers.  When sendmail receives a messages
> it does a lookup for the ip address of the sending mail server on the
> MAPS dns server.  

I notice that a number of the popular dns blacklists don't themselves
resolve.  At this point I don't really need to know why, but I'm
curious.

bl.spamcop.net doesn't have an A record, for exmaple, nor does
sbl.spamhaus.org or spamhaus.relays.osirusoft.com. Interesting - how
does my machine find the IP address for those name servers without A records?

Sorry if the question is something obvious!

Regards,

Carl