We have a windows 2003 small business server with service pack 1 and exchange server 2003. The exchange server was enabled andworking fine until yesterday. The clients lost the conenction with the exchange server and the ability of browsing into the active directory. If i close the windows firewall on the local connection of the server all the clients canlog on to the server andthe exchange server. I tried to add an exception to the firewall at port 25 but the problem remains. What can i do to fix this problem and have the windows firewall enabled?I have ready for your disposal the events that occured around the specific time.

get a real firewall (ISA server, checkpoint, sonicwall) and turn off the windows firewall. Exchange clients are using RPC which uses dynamic high port allocation. If your clients are inside the network, there is no reason to have a firewall between them and the exchange server. If they are outside the network open 443 and use RPC over HTTPS to make the connections.

You might check the ports to see if your ISP is blocking them. We run into this on a daily basis. If it's not a commercial account they will try to force you into a web browsing only mode by blocking your necessary ports for RPC over Https. Download the program at www.portdetective.com (it's free)and run it to check the ports for traffic blocking. This at least will tell you whether or not something is actually blocking the ports or there is something else going on. Also check your certificates. If they are not valid Outlook will not warn you it will just not connect. You can test RPC by attempting to connect to its location through http in a web browser. You should receive an error 403.2 read access forbidden. The try the location "server"/RPC/RPCPROXY.dll You should get a not authorized error 401.3. If this is the case then RPC is running and reachable and you should check the certificates. The directories vary depending on how and where you have RPC installed. typically "internet domain name/IIS vitual site/RPC See http://technet.microsoft.com/en-us/library/bb124649.aspx