How can I open the DCOM port for access in Windows XP / Vista / 2008 Firewall?

Solution:Before you enable ports in “Windows Firewall”, make sure that the “Windows Firewall: Allow local port exceptions” setting is enabled in Group Policies. To do this, follow these steps:

  • Click “Start”, click “Run”, type “gpedit.msc”, and then “OK”
  • Under “Local Computer Policy” expand “Computer Configuration” > “Administrative Templates” > “Network” > “Network Connections” > “Windows Firewall”, and then click “Domain Profile”
  • Right-click “Windows Firewall: Allow local port exceptions”, and then click “Properties”, or simply double-click it
  • Click “Enabled”, and then “OK”

That’s it.

Note: You can also use the “Windows Firewall: Define port exceptions” setting to configure local port exceptions.

The DCOM port is TCP 135. To open the DCOM port, follow these steps:

  • Click “Start”, and then click “Control Panel”
  • Double-click “Windows Firewall”, and then click the “Exceptions” tab.
  • Click “Add Port”.
  • In the “Name” box, type “DCOM_TCP135”, and then type “135” in the “Port number” box.
  • Click “TCP”, and then click “OK”.
  • Click “OK”.

Note: You can also type the following command at a command prompt to open a port:

netsh firewall add portopening TCP 135 DCOM_TCP135

.updated: February 6, 2014 author: jeff