We are running Windows 2008 domain. Some of users receive Undeliverable turned email with this message: #554 5.4.4 SMTPSEND.DNS.MxLoopback; DNS records for this domain are configured in a loop ##.
When I check the DNS status using nslookup on some of workstations, It shows mail.ejgallo.com internet address = 127.0.0.1
Workstation:
>nslookup
Default Server: 2008dc1
Address: 10.0.0.17
> set q=mx
> barefootwine.com
Server: 2008dc1
Address: 10.0.0.17
Non-authoritative answer:
barefootwine.com MX preference = 10, mail exchanger = mail.ejgallo.com
mail.ejgallo.com internet address = 127.0.0.1
> server 4.2.2.2
Default Server: b.resolvers.Level3.net
Address: 4.2.2.2
> barefootwine.com
Server: b.resolvers.Level3.net
Address: 4.2.2.2
Non-authoritative answer:
barefootwine.com MX preference = 10, mail exchanger = mail.ejgallo.com.
However, both of our DC/DNS doesn’t show mail.ejgallo.com internet address = 127.0.0.1
DC/DNS:
nslookup
Default Server: 2008dc1
Address: 10.0.0.17
> set q-mx
> barefootwine.com
Server: 2008dc1
Address: 10.0.0.17
Non-authoritative answer:
Name: barefootwine.com
Address: 50.19.110.254
Why the workstations show mail.ejgallo.com internet address = 127.0.0.1 but not DC/DNS?
Bob Lin, MVP, MCSE & CNE Networking, Internet, Routing, VPN Troubleshooting on
How to Setup Windows, Network, VPN & Remote Access on