Relay thru sys in whitelist

Vernon Schryver
Sat Jun 29 03:37:36 UTC 2002

> From: "Rose, Bobby" <>

> ...
> that user@domainA has a mailForwardAddress set to user@domainC.  domainC

> ...
> Does this help? DomainB isn't the source of the message that was sent
> out to the internet in bulk, domainA is so it would seem that dcc would
> want to look for domainA.  DomainB has to be whitelisted because it does
> send internal bulk messages. 

Should your system DomainC reject white-listed mail that mentions
domainA for other reasons, such as user@domainB reporting spam
to user@domainC?

Isn't the problem the same as what I wrote about below?  Does it
matter whether the forwarding is done by MX records, .forward files,
or something else?

> ...
> Spam filtering and MX forwarders is an awkward combination and not just
> for the DCC but for any filtering system including sendmail access
> databases.  If you white-list your MX forwarders by name or IP address,
> then you'll not reject any spam they send.  In that case, you probably
> need to install your filters on your MX forwarders.  If you don't white
> list your MX forwarders, you probably need to white-list any legitimate
> bulk mail they send, again for any filtering scheme.

What do you mean by "dcc would want to look for domainA?"  As I tried
to say, the DCC is about rejecting message bodies instead of domains.
The DCC is supposed to be fast enough to run on systems that handle
at least several 100,000 messages/day (and it does today), and so it
doesn't do regular expressions as Procmail does.

I don't think there is a third solution for any spam filter system
that honors white lists besides (1) put your filters on all of yor
incoming, white-listed SMTP gateways, or (2) don't white-list your
incoming SMTP gateways.  Neither is a pleasing solution, but that
comes from the conflict between white-listing and rejecting.

Vernon Schryver

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