spam.whitelist.rules and domain of sender does not exist

Peter Peters P.G.M.Peters at
Sun Jan 5 12:35:31 GMT 2003

On Fri, 3 Jan 2003 19:08:35 +0000, you wrote:

>At 19:03 03/01/2003, you wrote:
>>Thanks for the response, I removed dnl from the line referenced below and
>>rebuilt the and it is working now.  I am curious to know if
>>anyone is aware of any security issues involved in allowing unresolvable
>>domains to send mail?   What is the preferred setting for most people?
>Most people (AFAIK) don't allow messages from unresolvable domains as a
>mild anti-spam measure, as spammers used to use fake domain names. Anyone
>else got better reasons than that? It comes partly from the fact that if
>the domain name cannot be resolved, then you will never be able to deliver
>directly to the domain anyway, so why bother accepting the message at all?

This was the main reason when spammers used only fake domains. Nowadays
spammers use excisting domains so it won't work that well. But it turned
out to be a good measure to prevent users from typing errors in their
addresses. And to educate users who use munged addresses when using
e-mail instead of only with usenet.

Peter Peters
senior netwerkbeheerder,  Centrum voor Informatievoorziening,
Universiteit Twente,   Postbus 217,  7500 AE  Enschede
telefoon: +31 53 489 2301, fax:+31 53 489 2383,

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