Not able to receive mail from certain e-mail domains.

[Nerissa Parto]

We've installed a new Exchange server, moved the mailboxes, followed the
instructions on removing the first Exchange server, and made the changes
in our DNS entries.

We had problems with receiving mail from certain e-mail domains. At
first we thought it was the time it takes for the new DNS data to
delegate. And surely some eventually could send us messages. But it's
been a couple of weeks and there are still a couple of e-mail domains
that receive the following error:

>-----Original Message-----
>From: Mail Delivery Subsystem
>[mailto:MAILER...@slcfw1-2.kennecott.com]
>Sent: Thursday, April 08, 1999 10:59 AM
>To: us...@kennecott.com
>Subject: Returned mail: Host unknown (Name server:
>pub-v_mail.chemex.com.: non-recoverable error)
>
>
>The original message was received at Thu, 8 Apr 1999 10:59:15 -0600
(MDT) from uucp@localhost
>
> ----- The following addresses had permanent fatal errors -----
><npa...@chemex.com>
>
> ----- Transcript of session follows -----
>550 <npa...@chemex.com>... Host unknown (Name server:
>pub-v_mail.chemex.com.: non-recoverable error)

or this message:

> 451 <us...@chemex.com>...chemex.com: Name server timeout

The e-mail domains that I know that can't send us messages are
logicnet.com.mx, gdl.icanet.net.mx, and kennecott.com. Please note we
CAN send messages to them.

Thanks, in advance for your help.

[Rich Matheisen [MVP]]

Nerissa Parto <npa...@chemex.com> wrote:

[ snip ]

>><npa...@chemex.com>

The e-mail domain appears to be okay:

QUESTIONS:
chemex.com., type = MX, class = 1
ANSWERS:
-> chemex.com.
type = MX, class = 1, ttl = 83400, dlen = 15
preference 10, mail exchanger = pub-v_mail.chemex.com.
ADDITIONAL RECORDS:
-> pub-v_mail.chemex.com.
type = A, class = 1, ttl = 83400, dlen = 4
inet address = 204.50.94.2

BUT, there's no PTR record for the address 204.50.94.2:

QUESTIONS:
2.94.50.204.in-addr.arpa., type = PTR, class = 1
AUTHORITY RECORDS:
-> 94.50.204.in-addr.arpa.
type = SOA, class = 1, ttl = 43200, dlen = 54
nameserver = centurion.chemex.ca.
mailaddress = postmaster.centurion.chemex.ca.
serial = 97071105, refresh = 300, retry = 60,
expire = 1209600, minimum = 43200.

AND, look at the name of the server associated with the MX record:

pub-v_mail.chemex.com

The "_" character isn't permitted in a DNS name.

>The e-mail domains that I know that can't send us messages are
>logicnet.com.mx, gdl.icanet.net.mx, and kennecott.com. Please note we
>CAN send messages to them.

Then they have a forgiving SMTP server. Many would reject your FQDN on
the HELO/EHOL command with a 501 error because of the "_" in the name.

------------------
Rich Matheisen
MCSE, Exchange MVP