RBL cache {Scanned by HJMS}

[Richard Lynch]

Ugo, what you are not realizing is that RBL systems are implemented
using the DNS.  That's how they work.  They do not maintain some sort of
native database where they do lookups in response to queries.  Instead
they use an already existing, highly reliable, distributed database
system -- the DNS.

So, the client simply does a DNS lookup on a hostname and the response
indicated whether it is blacklisted or not.  For example (simplified for
illustration), the client issues a DNS query for
10.25.100.1.rblsite.net.  The response it gets will indicate whether
10.25.100.1 is blacklisted or not. This has huge advantages.  You get
all the benefits of a mature, distributed, caching, database system.  No
point in reinventing a distributed database system that already exists
and is in widespread use.

--
Richard Lynch <rich at mail.wvnet.edu>