At 14:24 -0500 2002/12/08, James P. Roberts wrote:
> > the same here, I would not have blocked the above if the HELO
>> argument had been in the same domain as the reverse lookup, after all
>> what's the point pretending to be something else since that is what
>> most spammers but very few bona fide servers do?
>>
> > Giuliano
...
>Well, I certainly want my server to advertise its true name
>(puns01.punsterproductions.com). I have been trying to get Covad to
>make the reverse DNS lookup return the correct name instead of the bogus
>one they made up. It is a static IP block, of course.
>
>If you forward lookup my server, it returns the correct IP address. It
>is only the reverse DNS, currently outside my control, which is screwed
>up. But at least an entry exists.
all right, I will modify the acl to do a lookup of the HELO arg and
match it with the IP, in case the first (reverse lookup) test fails.
This in principle can be abused by spammers, but so far I am not
aware of any of them using it.
To take into account also a possible reverse lookup failure (in which
case I defer) will mean a slightly more baroque logic though.
What I am not too happy about is the extra DNS lookup that this implies.
>Changing my server name to match the Covad made-up name won't solve the
>particular problem, with the Postfix MTA that actually rejected me. It
>seems it is the actual made-up name that triggered the block, rather
>than the IP address, per se, or the fact that the HELO didn't match.
>Not only that, but I really don't want to have to constantly monitor
>Covad to catch every time they change their reverse naming scheme.
cannot exim dynamically change his primary_hostname? I guess not.
>The real solution appears to be to get a competent business-class
>provider. But the cost may be prohibitive.
I think that any business targeted service offering static allocation
should offer customised reverse too. I will see in the next few weeks
since I am moving a client of mine from a shared T1 to ADSL.
And sorry for having rejected your email...
2002-12-08 19:24:17 H=h-64-105-159-234.phlapafg.covad.net
(puns01.punsterproductions.com) [64.105.159.234] F=<your@address>
rejected RCPT <my@address>: MESSAGE REJECTED BECAUSE LIKELY FORGED
SENDER. CONTACT OUR POSTMASTER IF THIS IS NOT TRUE.
Giuliano
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