Intermittent Sender Domain Must Exist errors from remote SMTP hosts

[robertd at home.com]

Kevin,

Thanks for a reply.  I'm using Microsoft Exchange 5.5, so I'm not sure
what the MAIL FROM answer from our server is, I'll check it out with a
sniffer trace.  I've not looked at the conversation between our server
and the remote SMTP server(s). I'm assuming it's going to be the
domain it's part of.  (e.x. example.com). I don't have any sub-domains
that are unknown in the "real" world or multiple outbound gateways on
our network, So I don't think that would explain the intermittent
nature of the problem.  I'm really at the end of my rope on this one.
I sent an Email to Ask Mr. DNS to see if maybe Cricket Liu (O'Reilly's
DNS and BIND guru) might be parsing his Email and maybe with a little
luck he'll see it and find it interesting enough to respond.

Thanks for all your help, I'll keep plugging away...

Robert


On 12 Jun 2000 15:45:50 -0700, Kevin Darcy <kcd at daimlerchrysler.com>
wrote:

>What are you giving as your MAIL FROM in these SMTP conversations? The
>zone "example.com" may be perfect, but if your MAIL FROM is giving
>"user at internal.example.com", where "internal.example.com" has no
>retrievable data on the Internet, then SPAM-paranoid mailers will
>probably reject it. It's become a necessity these days to rewrite sender
>envelope addresses, for just this reason. If you're balancing your load
>amongst multiple outbound gateways and only 1 of them is misconfigured,
>this might explain the intermittentness of the problem.
>
>Of course, I'm only speculating. Maybe you really do have a
>_bona_fide_ DNS problem. But since your zone has already passed
>DNS Expert, I think it's worth investigating the other possibility...
>
>
>- Kevin
>
>robertd040 at aol.com wrote:
>
>> Hi everyone,
>>
>> I'm having an intermittent problem with outbound email.  I will
>> intermittently get an error from a remote smtp host that indicates
>> that the reason for the rejection is "Sender Domain Must Exist", I've
>> also seen "DNS: FAILURE" or "Sender Domain must Resolve".  I've
>> checked and re-checked my zones, I've verified that my MX records are
>> correct (even though I don't see this as a problem because the MX
>> record is for OTHER people to find MY mail server with), I've
>> confirmed that my servers are delegated our reverse zone,
>> (in-addr.arpa) with our ISP, (Cable and Wireless)  , and from the
>> Internet all forward resolution works perfectly.
>>
>> I've been hearing a lot about anti-spam filters that SMTP hosts employ
>> to verify the validity of a SMTP message but I'm not sure this can be
>> ALL the problem.
>>
>> I've got 6 zones that I'm currently "hosting" with two name servers.
>> All the zones are registered with Network Solutions and all the zones
>> have the same two DNS servers.
>>
>> ex. (truncated whois output)
>>
>> XXXX.org
>>
>> ns1.XXXX.org    123.123.123.123
>> ns2.XXXX.org    123.123.123.123
>>
>> and
>>
>> XXXY.org
>>
>> ns1.XXXX.org    123.123.123.123
>> ns2.XXXX.org    123.123.123.123
>>
>> etc..etc..etc..
>>
>> I could include a huge amount of detail regarding my zones but it's
>> pretty basic and I've run tools like DNS Expert (miceandmen.com)
>> against the zones and they come up clean.
>>
>> My two real questions are;
>>
>> 1).  Have I done a bad thing by "hosting" several different domains
>> with the same two name servers. (I don't think so)
>>
>> 2). What are these remote smtp hosts doing so strange that they won't
>> correctly resolve who's authoritative for my zones? and why is it
>> intermittent. (usually I can re-send and the mail will go through).
>>
>> Thanks for anyones help.
>>
>> Robert
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