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Re: stupid SMTP rejection of spammers

2001-06-15 14:34:38

--On 01-06-15 14.20 -0700 Russ Allbery <rra(_at_)Stanford(_dot_)edu> wrote:

Patrik Fältström <paf(_at_)Cisco(_dot_)COM> writes:

(2) Don't say ok to a recipient address if you are not 100% sure you can
do local delivery.

This is not best current practice in many situations, the most obvious
being relays, gateways, and backup MX hosts.  This argument came up on
DRUMS too; hopefully it won't be necessary to rehash it again.  There is
no consensus in favor of this position.

Agreed there are a number of cases in normal design of networks this is ok.

But, what I have been forced to help some large companies in Sweden with is
a setup when they have one mail host which the MX refer to, and that host
accept any local part (but only their domainname). The host is then
relaying the mail to some internal host(s) which might give back a 5xx
response. The bounce is going to the envelope sender address, which is the
real target for something which can be seen as something between DOS and
spam attack.

Not fun.