Re: Exchange can't reach destination mail servers - Please Help!

Kirill, here are the details you requested:

Advanced Delivery Window:
Masquerade domain: <not configured>
Fully-qualified domain name: bdnt4.bdmfg.com
Smart host: <not configured>
Perform reverse DNS lookup on incoming messages: checked
I have also added several external DNS server addresses

There is a POP3 mail connector but it doesn't have anything special
configured. It has been pulling in mail just fine.

Like I mentioned in my other reply - The issue seems to be more ISA related
because a previous ISA backup does work fine in regards to exchange and DNS
communications. When I ran the Internet Connection Wizard mail and dns
lookups started failing intermittently.


"Ryan" wrote:

I think have narrowed the issue down but I'm still not sure how to fix it.
I racked the problems to a start date and found that the email delays
started after I ran the SBS Internet Connection Wizard. I had some rules
that I know were set up properly but they didn't block the way they were
designed. After running ICW to reset the ISA rules I set up my block rules
the exact same way but this time they worked. Unfortunately now emails seem
to be delayed. I created some ISA backups and have gone back a couple times
to reproduce this issue so its definitely something in ISA that's causing
this intermittent behaviour.

The rules I had after running ICW seemed to prevent recursive DNS queries
from passing in the DNS properties. Maybe that tells you something? The
block rule I set up just block a specific user account from having Internet
access after hours.

Any ideas what in ISA I need to configure for DNS to function properly?

Here's some nslookup results with an ISA backup before the 5th:
sympatico.ca
Server: localhost
Address: 127.0.0.1

Non-authoritative answer:
sympatico.ca MX preference = 5, mail exchanger = toip1.bellnexxia.net
sympatico.ca MX preference = 5, mail exchanger = toip2.bellnexxia.net
sympatico.ca MX preference = 5, mail exchanger = toip3.bellnexxia.net
sympatico.ca MX preference = 5, mail exchanger = toip4.bellnexxia.net
sympatico.ca MX preference = 5, mail exchanger = toip5.bellnexxia.net
sympatico.ca MX preference = 5, mail exchanger = toip6.bellnexxia.net
sympatico.ca MX preference = 5, mail exchanger = toip7.bellnexxia.net

toip1.bellnexxia.net internet address = 209.226.175.84
toip2.bellnexxia.net internet address = 209.226.175.85
toip3.bellnexxia.net internet address = 209.226.175.86
toip4.bellnexxia.net internet address = 209.226.175.87
toip5.bellnexxia.net internet address = 209.226.175.88
toip6.bellnexxia.net internet address = 209.226.175.174
toip7.bellnexxia.net internet address = 209.226.175.175

yahoo.com
Server: localhost
Address: 127.0.0.1

Non-authoritative answer:
yahoo.com MX preference = 1, mail exchanger = mx3.mail.yahoo.com
yahoo.com MX preference = 5, mail exchanger =
mta-v1.mail.vip.re3.yahoo.co
m
yahoo.com MX preference = 1, mail exchanger = mx1.mail.yahoo.com
yahoo.com MX preference = 1, mail exchanger = mx2.mail.yahoo.com

mx3.mail.yahoo.com internet address = 67.28.113.71
mx3.mail.yahoo.com internet address = 67.28.113.10
mx3.mail.yahoo.com internet address = 4.79.181.168
mx3.mail.yahoo.com internet address = 4.79.181.134
mx3.mail.yahoo.com internet address = 67.28.113.74
mta-v1.mail.vip.re3.yahoo.com internet address = 66.196.97.250
mx1.mail.yahoo.com internet address = 4.79.181.15
mx1.mail.yahoo.com internet address = 4.79.181.168
mx1.mail.yahoo.com internet address = 67.28.113.73
mx1.mail.yahoo.com internet address = 67.28.113.19
mx1.mail.yahoo.com internet address = 4.79.181.14
mx2.mail.yahoo.com internet address = 4.79.181.135
mx2.mail.yahoo.com internet address = 4.79.181.136
mx2.mail.yahoo.com internet address = 4.79.181.168
mx2.mail.yahoo.com internet address = 67.28.113.70
mx2.mail.yahoo.com internet address = 67.28.113.72

renegodbout.com
Server: localhost
Address: 127.0.0.1

Non-authoritative answer:
renegodbout.com MX preference = 10, mail exchanger = mxmail.register.com

inco.com
Server: localhost
Address: 127.0.0.1

Non-authoritative answer:
inco.com MX preference = 10, mail exchanger = smtp.sin.inco.com
inco.com MX preference = 5, mail exchanger = smtp.tor.inco.com
inco.com MX preference = 10, mail exchanger = ap.test.inco.com
inco.com MX preference = 10, mail exchanger = na.test.inco.com

smtp.sin.inco.com internet address = 203.208.251.199
smtp.tor.inco.com internet address = 129.33.168.70
ap.test.inco.com internet address = 203.208.251.200
na.test.inco.com internet address = 129.33.168.76

Now some NSLookup results form a ISA backup made on the 30th (after running
ICW and setting up some custom block rules):

inco.com
Server: localhost
Address: 127.0.0.1

Non-authoritative answer:
inco.com MX preference = 10, mail exchanger = smtp.sin.inco.com
inco.com MX preference = 5, mail exchanger = smtp.tor.inco.com
inco.com MX preference = 10, mail exchanger = ap.test.inco.com
inco.com MX preference = 10, mail exchanger = na.test.inco.com

smtp.sin.inco.com internet address = 203.208.251.199
smtp.tor.inco.com internet address = 129.33.168.70
ap.test.inco.com internet address = 203.208.251.200
na.test.inco.com internet address = 129.33.168.76

sympatico.ca
Server: localhost
Address: 127.0.0.1

DNS request timed out.
timeout was 2 seconds.
*** Request to localhost timed-out

yahoo.com
Server: localhost
Address: 127.0.0.1

DNS request timed out.
timeout was 2 seconds.
*** Request to localhost timed-out

renegodbout.com
Server: localhost
Address: 127.0.0.1

DNS request timed out.
timeout was 2 seconds.
*** Request to localhost timed-out




"Dave York" wrote:

Helps if I don't typo the mx lookup...

So here's my correction, the mx lookup to sympatico.ca should look
something like:

Server: <your DNS server>
Address: xxx.xxx.xxx.xxx

Non-authoritative answer:
sympatico.ca MX preference = 5, mail exchanger =
toip1.bellnexxia.net
sympatico.ca MX preference = 5, mail exchanger =
toip2.bellnexxia.net
sympatico.ca MX preference = 5, mail exchanger =
toip3.bellnexxia.net
sympatico.ca MX preference = 5, mail exchanger =
toip4.bellnexxia.net
sympatico.ca MX preference = 5, mail exchanger =
toip5.bellnexxia.net
sympatico.ca MX preference = 5, mail exchanger =
toip6.bellnexxia.net
sympatico.ca MX preference = 5, mail exchanger =
toip7.bellnexxia.net

toip1.bellnexxia.net internet address = 209.226.175.84



Dave York wrote:
Check and make sure your mail server has reverse lookup working? I
wrote up an article on it here:
http://meektech.blogspot.com/2006/10/howto-reverse-lookup-woes.html

Also - You shouldn't need to configure the external DNS servers on your
SMTP virtual server if your DNS is set up correctly, so if the reverse
lookup stuff doesn't help you may want to investigate down that path.
Also, try running an nslookup against the DNS server you are pointed
to, and make sure you can resolve the MX records for those domains
you're attempting delivery to.

commands would be something like this at a DOS prompt:
nslookup
set q=mx
symaptico.ca

should return something like:
Server: <your DNS server>
Address: xxx.xxx.xxx.xxx

symaptico.ca
primary name server = ns1.sl.ca
responsible mail addr = dns-admin.ns1.sl.ca
serial = 2001050800
refresh = 10411 (2 hours 53 mins 31 secs)
retry = 3600 (1 hour)
expire = 604800 (7 days)
default TTL = 900 (15 mins)


Ryan wrote:
I manage a SBS 2000 server running the latest Service Packs and Updates. In
the last couple weeks the server has been queuing more mail than usual and
it's becoming a problem to the company. It seems that the emails eventually
go through but the delay is unacceptable.

This SBS 2000 server is also running ISA - if that means anything to you. I
have troubleshooting rule I sometimes use in ISA that allows all traffic
through but this rule had no effect on the mail delays.

The DNS forwarders tab has the DNS servers as well as some extras I added.
I also added the same set of addresses to the SMTP virtual server (mail
didn't seem to move without the DNS server entered in there)

From the errors below you can see that a single domain doesn't always
generate the same error so I'm really having trouble pinpointing the issue.
Please Help!

Here are some examples of the Event 4000 SMTPSVC errors I'm getting:

Message delivery to the remote domain 'yahoo.com' failed for the following
reason: The connection was dropped by the
remote host.
Message delivery to the remote domain 'yahoo.com' failed for the following
reason: The specified network name is no longer available.
Message delivery to the remote domain 'sympatico.ca' failed for the
following reason:
Message delivery to the remote domain 'sympatico.ca' failed for the
following reason: Unable to bind to the destination server in DNS.
Message delivery to the remote domain 'INCO.COM' failed for the following
reason: Unable to bind to the destination server in DNS.
Message delivery to the remote domain 'unitz.ca' failed for the following
reason: The connection was dropped by the remote host.
Message delivery to the remote domain 'unitz.ca' failed for the following
reason: Unable to bind to the destination server in DNS.
Message delivery to the remote domain 'renegodbout.com' failed for the
following reason: Unable to bind to the destination server in DNS.


I can telnet to some of them:
telnet mx1.mail.yahoo.com 25 - sometimes connects but "connection to host
lost"
telnet mta1.sympatico.ca - connects but "connection to host lost"
telnet smtp.tor.inco.com 25 - sometimes connects
telnet mx.untiz.ca 25 - connects
telnet mxmail.register.com 25 - connects

Here is a sample NDR one of the users sent me:
Your message did not reach some or all of the intended recipients.
Subject: Hey
Sent: 24/10/2006 10:33 AM
The following recipient(s) could not be reached:
Matt Roach (matt.roach@xxxxxxxxxxxxxxxxxxx) on 24/10/2006 10:34 AM
There was a SMTP communication problem with the recipient's
email server. Please contact your system administrator.
<mail.domain.com #5.5.0 smtp;550 relaying to
<matt.roach@xxxxxxxxxxxxxxxxxxx> prohibited by administrator>

Any ideas?


.

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