sendmail - reverse lookup problems

[Barry Margolin]

In article <9pvgr8$9av at pub3.rc.vix.com>,
Boex,Matthew W. <Matthew.Boex at cna.com> wrote:
>another odd problem with reverse lookup's.  we are able to send mail to
>na.bestfoods.com [12.14.84.10].  They cannot send mail to us.  They can do
>an nslookup and get our mx record.  Sendmail, on our end, I think is timing
>out trying to reverse lookup their outbound mail server.  They tell me the
>server is 12.14.84.35.   when i do an nslookup 12.14.84.35 i get nothing.
>when i do a dig -x 12.14.84.35 it reports that att.net is authoritative for
>their domain, and the PTR record is aliased?  i think.  

They're doing RFC 2317-style reverse DNS, but there's no PTR record for the
..35 address.  The only reverse entry they have in that block is for the .10
address.

>why is nslookup showing nothing

Because nslookup sucks.  You knew that already, didn't you?

>why is sendmail choking on an aliased PTR record?  Should it be choking?  

The problem isn't that it's aliased, it's that the thing it's aliased to
doesn't exist.  You have sendmail configured to require a reverse DNS entry
for the client, and they don't have one.

-- 
Barry Margolin, barmar at genuity.net
Genuity, Woburn, MA
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