On Mon, 19 Jan 1998, Sherwood Botsford wrote:
> I am beginning to think that some of this is deliberate: That
> some outfit secures a DNS entry, posts a flood of mail, then removes it.
That may well be true, but in the last week I have seen about half a
dozen cases, apparently in very different parts of the domain space,
where nameservers are giving SERVFAIL instead of NXDOMAIN for
non-existent DNS entries. Often there is an A record but no MX record,
and this hangs Exim up, because it can't proceed to look for an A record
until it knows for certain there is no MX record. I mailed the superior
domain of one of them, but for many you can't mail them because of the
problem. I wish I knew what was provoking this.
> With suitable post processing of message log files, you could
> determine which sites come and go, and which ones are fly-by-nights.
Volunteers? (Do you mean message log files, or main log files, by the
way?)
> Then a single added feature, dns_failure_reject=[domainlist]
> would allow you to treat certain dnsfailures as permanent failures if
> they didn't check out the first time.
I like the idea of dns_failure_reject, or rather, dns_failure_treat_as_
non_existent, and have added it to the Wish List.
--
Philip Hazel University Computing Service,
ph10@??? New Museums Site, Cambridge CB2 3QG,
P.Hazel@??? England. Phone: +44 1223 334714
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