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Re: 2.99.50(snap4) now at ftp.funet.fi (was: Re: Spam help.)

On Tue, 26 May 1998, Andy Poling wrote:

> On Mon, 25 May 1998, Alvin Starr wrote:
> > Is it safe to assume that No valid Email source will be sending mail from 
> > a non resolved address?
> No.  In fact, it is not uncommon to receive mail from a host whose
> nameserver is unreachable or slow to respond, leading to your inability to
> perform a reverse lookup...

In real life though, I found that I was able to use sendmail rules to
block incoming email from relays that had no resolvable in-addr.arpa DNS.
The result was lots of blocked spam, and a few really annoying sites that
wouldn't know in-addr.arpa if it bit them in the rear end, telling my
customers that our server was broken as they could send mail to everywhere
else.  I educated a few sites, but ended up giving up, and commenting out
that rule.

 Jon Lewis <jlewis@fdt.net>  |  Spammers will be winnuked or 
 Network Administrator       |  drawn and quartered...whichever
 Florida Digital Turnpike    |  is more convenient.
______http://inorganic5.fdt.net/~jlewis/pgp for PGP public key____