troubleshooting Question

Exchange 2010 DNS error

Avatar of ITMND
ITMND asked on
ExchangeSBSMicrosoft Server OS
21 Comments2 Solutions618 ViewsLast Modified:
I just installed an SBS 2011 server and incoming mail works fine, but outgoing outside of local addresses won't go.  I've tried various DNS settings, telling it to use external DNS, disabling IPv6, nothing seems to work.  My firewall says it's passing port 25 traffic outbound and AT&T verified they are no longer blocking port 25.  I've tried using a smarthost and without a smarthost.  The message I'm getting is:

451 4.4.0 primary target IP address responded with "421.4.4.2 unable to connect."attempted failover to alternate host, but that did not succeed. Either there are no alternate hosts, or delivery failed to all alternate hosts
Join the community to see this answer!
Join our exclusive community to see this answer & millions of others.
Unlock 2 Answers and 21 Comments.
Join the Community
Learn from the best

Network and collaborate with thousands of CTOs, CISOs, and IT Pros rooting for you and your success.

Andrew Hancock - VMware vExpert
See if this solution works for you by signing up for a 7 day free trial.
Unlock 2 Answers and 21 Comments.
Try for 7 days

”The time we save is the biggest benefit of E-E to our team. What could take multiple guys 2 hours or more each to find is accessed in around 15 minutes on Experts Exchange.

-Mike Kapnisakis, Warner Bros