Using RPC over HTTP for laptop both in & out of the office

This comes from smallbizserver2003 private/directaccess newsgroup:

PROBLEM: I have a customer who has a number of notebook users (Win XP Pro) who wants to setup the notebooks so Outlook can be used to their SBS2003 server from both the inside network and also the outside using IPC over HTTP.

The SBS server is on their inside network with single LAN card and connected via a firewall router to an ADSL internet connectionin – a fairly standard sort of setup. The router is doing NAT to 192.168.1.x . They have a FQDN that points to the firewall and port forwards to the SBS server – The server is known internally as sbs.dommainname.local.

I have no problems configuring the notebook to use Outlook over HTTP from outside, the problem is from the inside LAN – it just hangs. If I create a new profile while connected to the LAN and try to configure Outlook as per the help file you get from the https://server.domainname/remote page it hangs when I use the external FQDN for the ‘URL to connect to my proxy server for Exchange’ .

If I ping the FQDN from inside I get the outside IP of the router.

How do I configure the one profile so Outlook can be transparently used on the Internal network and also externally on the Internet?


The problem is expected since the public FQDN will be resolved to the external IP address of the firewall device while actually the notebook is on the internal network. If you do not want to create a new profile for the  user we can create an “Alias (CNAME)” record in DNS so that the public FQDN will be resolved to the Internal IP address of the server when on the LAN:

1. On the SBS server, open DNS Management Console by running dnsmgmt.msc.

2. Expand the <ServerName> node, expand the “Forward Lookup Zones” folder and then highlight the domain FQDN zone (domainname.local).

3. Right click on the zone and choose New Alias (CNAME).

4. Name the Alias your public FQDN (for example,

5. Type your SBS server’s internal FQDN (for example, servername.domainname.local) as the “Fully qualified domain name (FQDN) for target host”. Click OK.

6. Right click on the <ServerName> node and choose All Tasks->Restart.

7. Check if a ping of returns the internal IP address of the server. Then check if Outlook work well internally.

Please do not hesitate to let me know if you have any further concerns.
Sincerely, Cliff Zhang – Microsoft Partner Online Support – MCSE 2000 

5 thoughts on “Using RPC over HTTP for laptop both in & out of the office

  1. Hello Cliff, I followed your instructions above. When I ping the, I still get the external IP address. Do I have to have any other entry in the local DNS server referring to the public FQDN?

    Thanks, Jerry (email:

  2. Unfortunately I am running into the same problem as well, where I am resolving the external IP with the CNAME setup. I guess I’ll just have to go back where I have an extra DNS zone for

  3. After Creating the CNAME in your DNS server. If your ping returns the external ip you need to check two things.

    1.if your client pc has a static ip check the primary dns resolver should be your internal dns server.

    2. if you are using dhcp go there and check if your internal dns server is used in the dhcp options.

    once you do this clear the dns cache and then ping again.


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