iis smtp nntp: Our company recently replaced the server running our external SMTP e-mail
connector. Since that time, we have been seeing repeated warnings from the
SMTPSVC, Event ID 4000 and 4006, as follows:

Event Type: Warning
Event Source: smtpsvc
Event Category: None
Event ID: 4006
Date: 2/9/2008
Time: 1:44:22 AM
User: N/A
Computer: NEO
Description:
Message delivery to the host '64.136.44.37' failed while delivering to the
remote domain 'juno.com' for the following reason: An SMTP protocol error
occurred.

and

Event Type: Warning
Event Source: smtpsvc
Event Category: None
Event ID: 4000
Date: 2/9/2008
Time: 12:00:03 AM
User: N/A
Computer: NEO
Description:
Message delivery to the remote domain 'sdrs.g' failed for the following
reason: Destination server does not exist.

At the same time, users in our remote offices, using the same Exchange
server as those locally in the main office, cannot send e-mail to certain
outside domains.

The external SMTP server is running WS2K3 w/SP2, and is multi-homed (1 NIC
on the internal network and 1 on the DMZ).

Any ideas.

Thanks for your reply and info. Basically, an array of 2 ISA servers through
which our Exchange server routed outgoing email was removed from the network
and replaced by a new array of two new ISA servers. The new ISA servers are
domain members, while the old ones were not. The names are not the same.
Also, as we are migrating from one ISP to another, the DMZ network that the
ISA servers are connected to is different. However, all ISA and SMTP
settings are the same as on the old servers, except IP config, of course.

I no this may make me sound like a bit of a rookie, but after looking up
PTR-HELO roundtrip test, I get the concept, but am unsure how to find out if
we pass. Also, ur NetOps manager found yesterday that PTR records were not
updated on the outside DNS, and has since corrected that, but the problem
still persists.

Also, I called MS yesterday, and was told to change the "Forward all mail
through this connector to the following smart hosts", followed by the IP of
the ISA array, to "Use DNS..." when the issue happens.

Finally, I am starting to check the SMTP logs now. Thanks for that tip.

[quoted text, click to view]

Please be precise about what you mean by "replaced": did the public or
private IP change? The hostname? The SMTP server's FQDN? Do you still
pass the PTR-HELO-A DNS "roundtrip" test?

[quoted text, click to view]

You would have to look into your SMTP logs (get used to it!) to get
extended information about that session.

[quoted text, click to view]

I can assure you that that remote domain is invalid.

--Sandy



------------------------------------
Sanford Whiteman, Chief Technologist
Broadleaf Systems, a division of
Cypress Integrated Systems, Inc.