Re: Problems with mail system? [Fwd: Returned mail: User unknown]
On Thu, Sep 07, 2000 at 11:58:33AM +0200, Paul Slootman wrote:
> > In any case, reverse DNS lookup is reasonable, no matter what you
> > think of DUL.
> I have to agree with this. The previous time, the discussion was using
> DUL to block email. This is about reverse DNS lookups failing, which
> is a completely different this. If the reverse DBS lookup fails, you
> either have a grossly incompetent ISP(*) or a malicious one.
i'd have to disagree with this. screwed up the DNS isn't a good reason
for bouncing mail (because there's no particular reason to believe it's
spam)....the fact that the ISP is clueless doesn't mean that they're
spammers or a spam haven.
the only thing that reverse DNS really tells you is that the remote
site isn't pretending to be someone else (i.e. tcpd style PARANOID
checks)....and that check is satisfied whether there's a PTR record or
OTOH, DUL is good because their is bugger-all legitimate reason for
anyone to be sending direct from a dialup dynamic IP address - there are
many cheap & reasonable alternatives to doing that.
more importantly, given that the number of die-hard DIYers with linux
boxes who insist on delivering their mail from a dynamic IP address (and
wont consider any alternative for any reason) is insignificant compared
to the number of spammers who try to do the same, there is excellent
reason to believe that the incoming mail is probably spam.
> I recommended my client to go elsewhere for internet connectivity. He
> did, and now knows that it is possible to have a reliable internet
> connection. He now also pays in excess of US$1000 a year _less_ for
buggered DNS is, however, a damn good reason to look for a better ISP.
one with a clue. if your current ISP can't even get something simple
like DNS working properly then it's unlikely that they can get anything
working....they don't deserve your money.
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