Does anybody knows, for what purposes Microsoft is using the TCP port 1242 (nmasoverip) in Microsoft Exchange Server 2003? When I close this port on firewall, my MDA (MS Outlook 2003) is loses connection with server. In official sources (http://technet.microsoft.com/en-us/library/bb124075(EXCHG.65).aspx) this information is not described. Many thanks to response.

Hi, If you are not using static ports, it will more than likely be a port listening for RPC (after the initial connection on port 135). Example: 10.82.0.116[1242] [f5cc5a18-4264-101a-8c59-08002b2f8426] MS Exchange Directory NSPI Proxy :YES To remove this you would have to configure static ports. If you do want to configure static ports I suggest using numbers above port 5000. Configure Static Ports: http://support.microsoft.com/kb/270836 More information on Port 1242: http://www.proexchange.be/blogs/exchange2007/archive/2009/05/18/configuring-static-ports-for-exchange-2007.aspx Unless you have a stringent requirement to close this port I would leave it how it is and forego setting static ports. The only out of the box life need for static ports is Exchange 2010 when using hardware load balancers and you have an RPC Client Access Array, or you have users on the other side of a firewall that need to connect to an Exchange Server on the other side via MAPI. You also could configure RPC over HTTPs / Outlook Anywhere and route everything over 443 if that meets your reqirements and goals. Oliver Moazzezi | Exchange MVP, MCSA:M, MCITP:Exchange 2010, BA (Hons) Anim | http://www.exchange2010.com | http://www.cobweb.com | http://twitter.com/OliverM