Extended Monitoring Guide
Note
This procedure is only applicable for environments with firewalls and so most users will not need this step.
DCOM dynamically allocates one port per process. You need to decide how many ports you want to allocate to DCOM processes, which is equivalent to the number of simultaneous DCOM processes through the firewall. You must open all of the UDP and TCP ports corresponding to the port numbers you choose. You also need to open TCP/UDP 135, which is used for RPC End Point Mapping, among other things. In addition, you must edit the registry to tell DCOM which ports you reserved. You do this with the HKEY_LOCAL_MACHINES\Software\Microsoft\Rpc\Internet registry key, which you will probably have to create.
To allow remote registry access for the performance data to be read, see Controlling remote Performance Monitor access to Windows NT servers.
The following table shows the registry settings to restrict DCOMs port range to 10 ports.
Table 50.4. Firewall and Registry Settings for DCOM
| Registry Key | Type | Setting |
|---|---|---|
Ports |
| Range of port. Can be multiple lines such as: 3001-3010 135 |
PortsInternetAvailable |
|
|
UseInternetPorts |
|
|
These registry settings must be established in addition to all firewall settings.