I was attempting to get outlook anywhere to work. My environment is Exchange 2007 SP3 with the latest rollup package (as of 2/27/13) running on W2K8R2. I am using a UCC certificate from godaddy with my external name “mail.mydomain.com” and my Subject Alternative Names are autodiscover.mydomain.com; MYINTERNALSRVNAME.mydomain.com; etc…

This is a small environment so every exchange role is installed on the same server.
The error pops up when I run the RPC over HTTP test at

and get an error on the following test:

Attempting to ping RPC endpoint 6004 (NSPI Proxy Interface) on server.

I checked a few things on this:
1. I made sure that the “valid ports” registry key in HKLM/Software/Microsoft/RPC/RpcProxy had the following:


2.I added my internal server name to my DNS hosts (I’m not sure if this made a difference) I’m going to remove it and test at a later time.

3. Following someone’s advice (and what I really think solved the problem) was that I edited the hosts file on the exchange server and put in 2 entries ( is my internal ip address for my exchange server) MYMXINTERNALSRVNAME MYMXINTERNALSRVNAME.mylocaldomain.com

This seemed to solve the problem with that 6004 error. I believe it has something to do with an IPv6/IPv4 incompatibility problems with Outlook Anywhere/rpcoverhttp.

More info at: