[NTLUG:Discuss] weird sendmail domain problem

[kbrannen@gte.net]

Greg Edwards wrote:
> kbrannen at gte.net wrote:
> 
>> I've been working on RH7.2 (fully patched) machine with the weirdiest 
>> sendmail (v8.11.6) error I've ever seen...and I'm looking for any 
>> ideas.  Yes, I'm sorta desparate. :-)
>>
>> Whenever anyone from the outside sends email to this machine, it 
>> replies with:
>>
>> 553 Requested action not taken: mailbox name not allowed
>>
...
>>
>> Anyone have any clues?  I found all kinds of interesting sendmail 
>> things on Google, but none of it helpful. :-/
>>
>> TIA,
>> Kevin
>>
> 
> Kevin,
> 
> I don't think DNS since it complains about mailbox and not host.  Try 
> running sendmail interactive to see the conversation between systems.
> 
> /usr/sbin/sendmail -v -d1 root at f.com

Yep, actually I did "/usr/lib/sendmail -v -d10".

> 
> This will give you allot more help than the telnet session.  Increase 
> the -dX value to fill you screen up with lots of info ;)

As merlin suggested, I tried putting the name in <>, no joy.

But wait!  I was just talking with another guy about all this on the phone. 
He did a test and saw the failure.  Started asking me about the setup, what 
I'd done, etc.  After a few minutes of talking, we tried another test and I 
got a different HELO banner, and it started taking the RCPT names, and 
delievered the mail correctly.  And I *swear*, I DIDN'T DO ANYTHING TO IT!!! 
No restart of the server, no config file changes, nothing!

<pausing for phone call :->

OK, I just talked with the guy where the machine is physically located and he 
did 2 things:
1. he installed a reverse lookup (PTR) record in his DNS.
2. he told me that he has a firewall with an SMTP proxy (of course nobody told 
me that, argh!) and he put the machine's address into the proxy server.

Now, the problem could have required both changes, but my money is on #2.  The 
HELO banner changing seems pretty important, which then leaves me with the 
question of what was I talking to during my tests?  (Before you attempt to 
answer that, consider that I was telnet'ing to something when I started 
sendmail on the machine, and couldn't telnet to anything when I stoped 
sendmail on the machine.)

A happier but still slightly puzzled Kevin. :-)