Here is some background on my issue: I recently migrated from Win 2000 DC, DNS, DHCP, WINS to 2008 DC, DNS, DHCP, WINS. The Win 2000 server is still up but the DHCP server and WINS server are stopped. All servers and clients have been changed to use only the Win 2008 DNS server. We are running Exchange 2003. My issue is that some e-mail is not being delivered to only certain domains after the migration. For example, e-mail to yahoo.com is not being delivered. If I look in the queues I can see that the SMTP connector for Yahoo e-mail is stuck as well as a few others. I either get an "Unable to Bind to destination server in DNS" error or "The remote server did not respond to a connection attempt" error depending on the destination domain for these messages. I have run dcdiag & smtpdiag with no apparent errors. Now, if I add external DNS servers to the default SMTP virtual server the e-mails go fine. This says to me that there is something gumming up on our DNS server. However, as I mentioned before I get no errors on dcdiag or smtpdiag and using nslookup on the exchange server resolves the addresses just fine. Any ideas on what might be causing the issue? TIA

Try disabling EDNS on the 2008 server. dnscmd /config /EnableEDNSProbes 0 James Chong MCITP | EA | EMA; MCSE | M+, S+ Security+, Project+, ITIL msexchangetips.blogspot.com

Sigh, Microsoft. Gotta love it when you get a working answer right off the bat. You're the man. Thanks.

On Wed, 6 Apr 2011 20:53:51 +0000, Rusty Shackleford Deuce wrote: >Sigh, Microsoft. Gotta love it when you get a working answer right off the bat. You're the man. Thanks. It's not MS, it's usually some router/firewall that doesn't like UDP packets that are larger than 512 bytes. Domains that have lots of mail servers (like Yahoo, MSN. AOL, etc.) need more than 512 bytes to send all the information. --- Rich Matheisen MCSE+I, Exchange MVP --- Rich Matheisen MCSE+I, Exchange MVP