strange error... any idea?

[Youn Gonzales]

----- Original Message -----
From: "Miguel Koren O´ Brien de Lacy" <miguelk at KONSULTEX.COM.BR>
To: <MAILSCANNER at JISCMAIL.AC.UK>
Sent: Wednesday, February 13, 2002 4:01 PM
Subject: Re: strange error... any idea?


> Another thing you may want to look at is if your installation requires a
> "reverse dns lookup" for accepting mails. I not sure though where in
> sendmail this is configured :-(  Of course it could also be that a
firewall
> is in place and blocking that ip? Check your end and their end of it. Ask
> them to do a "telnet your_ip 25" and see what comes up. Try this also to
> their ip and see what you get.

That feature is called accept_unqualified_senders and is configured in the
sendmail.mc file used to generate the sendmail.cf file. Also of interest are
the accept_unresolvable_domains feature, access_db feature,
blacklist_recipients feature, and rbl feature. You can find more info on
these features at http://www.sendmail.org/m4/features.html.

I am by no means a sendmail guru, but you could probably modify the
sendmail.cf file and look for the error 550 - there should be several
instances. You could modify the wording on them so that you could tell which
of the rulesets were causing the reject. I believe there is also a way to do
this by running sendmail in test mode (sendmail -bt) and using check_mail.

from sendmail(8)
       -bt    Run in address test mode.  This mode reads addresses and shows
the
              steps in parsing; it is used for debugging configuration
tables.

Youn Gonzales
System Administrator
Comptia A+, Network+, INET+,
Cisco CCNA/CCDA Certified Technician
Microsoft Certified Professional