troubleshooting Question

TMG ISP Redudancy and DNS

Avatar of Techrunner
Techrunner asked on
Microsoft Forefront ISA ServerNetwork ArchitectureNetwork Security
11 Comments1 Solution843 ViewsLast Modified:
Hello Experts,

actually this is the continuation of my previous question


I have installed TMG with 3 NICs such as ISP1, ISP2 and Internal

I configured the ISP1 and ISP2 interfaces with IP addresses and default gateways and

configured internal NIC with IP address, but no  Default Gateway.

I installed DNS service on TMG and configured the forwarders pointing to ISP DNS servers.

Finally Internal NIC DNS configuration as follows

Primary :

Alternative: Internal AD DNS servers

Configured persistent routes

Persistent Routes:
  Network Address          Netmask             Gateway Address  Metric                             1                  ( Internal LAN)
            2                   ( ISP1 DNS Server)
            3                    ( ISP2 DNS Server)

Suddenly I started facing a problem that web proxy client receiving a pop up Authentication Required.

I tried nslookup on TMG server for my domain domain but cannot resolved.

I would highly appreciate any help.

Craig Beck
Network Architect
Join our community to see this answer!
Unlock 1 Answer and 11 Comments.
Start Free Trial
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 1 Answer and 11 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