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I have a requirement to set the Outlook client to use a specific RPC port that will allow me to poke Outlook through our secure Application Level Gateway (Appgate). I have found article : KB 833799

That tells you how to setup a profile with a PRF file to use certain ports.

My question is this - do I need to force Exchange to use those ports (IE set Exchange to use those ports only) or can exchange continue to work on a random port basis.

If I do need to change them, how the heck do I do it and does it require a reboot?

Will it cause any adverse affects if i do this?

Also, does this need to be done on all exchange servers or can i get away with doing it on just the one that has mailboxes that need to access it in this way.

Thanks in advance for your help and suggestions.


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up vote 1 down vote accepted

Before you go off and do this, you might want to consider using RPC over HTTP (aka "Outlook Anywhere"). This gateways the MSRPC protocol over HTTP (or HTTPS) and might make life easier for you re: forwarding this traffic thru the firewall.

Here's the server-side instructins for statically assigning ports:

You would be making this change only on the Exchange Server computer(s) that the Outlook clients would be talking to. The change will require a "bounce" of the Exchange services but should not require a reboot of Windows.

Have a look at this article re: RPC over HTTP:

You'll like RPC of HTTP better, I think, and it's more "supported".

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Thanks. As per my comment above we already use RPC over HTTP but for this situation is not appropriate. Thanks for the link, I will check it out and attempt to get those changes made. Nice one. – Kip Jun 23 '09 at 12:51

With Exchange 2003 SP1 and upwards you can connect Windows XP SP2 and Outlook 2003 SP1 Clients through RPC over HTTP(s) so you only need port 80 or 443. The Setup is a litte bit complex. I need to look it up at MS.

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Thanks for your rediculously quick reply. We already use the RPC over HTTP but unfortunately one of our addons to Outlook is not compatible with this method. – Kip Jun 23 '09 at 12:50

RPC usually uses port 6001 and 6004, to change these ports you do so by editing the registry entry at:


If you have multiple front end Exchange servers you will need to do that on each of them.

As the others have suggested, RPC over HTTP may be a better solution to the problem here.

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So your Application Gateway doesn't support Applications?

(edited) a bit harsh maybe, but this is the antithesis of an Application gateway. Perhaps it only speaks HTTP? And perhaps it's the reason RPC/HTTP isn't usable with the app?

With RPC-based protocols, if you manage to set the server port to a specific number, the endpoint mapper should still direct clients there.

Where Outlook used to be problematic was with a callback from the server to the client for new mail notifications; not sure if that's still the case, it was ages ago when I looked.

So, if you manage to set the Exchange server port Outlook wants to connect to, Outlook (as an RPC client) should just pick that up after interrogating 135, no client mods needed.

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:) It does support many applications and works very well but a number of accumulated issues and circumstances brought me to this point. That is usefull to know that setting the server should force the client as this will in fact solve my problem. Nice one. – Kip Jun 23 '09 at 14:36

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