Need to Open Port

I just started getting this problem after using Comodo and the program in question for several months.

When I try to log into the game, I get an error saying:

“Failed to connect due to network error. Please ensure that UDP port 3100 on your firewall is open.”

Like I said, I never had this problem until this morning and I am able to connect just fine if I disable the Comodo Firewall. My question is how do I go about resolving this and/or opening the specific port?


You must create Global Rules, try this:

Firewall → Network Security Police → Global Rules then ADD

Action: Allow
Protocol: UDB
Dirtection: IN
Source address: Any
Destination address: Any
Source Port: Any
Destination Port: check A Single Port 3100

Now you will be able to play your game! :wink:

If you have more problems, we are here! :-TU

In the case of the STEAM application I need to open all these ports below: (taken directly from the steam website):

Steam Client
* UDP 27000 to 27015 inclusive (Game client traffic)
* UDP 27015 to 27030 inclusive (Typically Matchmaking and HLTV)
* TCP 27014 to 27050 inclusive (Steam downloads)
* UDP 4380

Dedicated or Listen Servers

  • TCP 27015 (SRCDS Rcon port)

Steamworks P2P Networking and Steam Voice Chat
* UDP 3478 (Outbound)
* UDP 4379 (Outbound)
* UDP 4380 (Outbound)

I went to the firewall>>Networks security Policy>> Global rules>>Add
But the problem is it asks me the direction (In/Out) and also the SOURCE and DESTINATION ports. How do I know if the direction of the above ports are In/out or both, and do I put them in the SOURCE, DESTINATION or both??


I will correct Jovan a bit. His description is not wrong but this how you should do it when you add a port in global rules. Do not add this port it is just an example!!!

By EricJH

To open the port TCP 1723 for example

First step is to determine the MAC or Physical address of you network connector. Go to Start → Run → cmd → enter → a black box will show up and enter the following → ipconfig /all (notice the space before /all) → enter → now look up the Physical address and write it down.

Notice that Physical address = MAC address

Firewall → Network Security policy → Global Rules → Add → fill in the following:
Action: Allow
Protocol: TCP
Direction: In
Description: Incoming Port

Source address: Any
Destination Address: Choose MAC address and fill in the found MAC/Physical address
Source Port: Any
Destination Port: 1723

Then push Apply → Now make sure that the new rule is somewhere above the basic block rule(s) as the bottom (the block rules have red icons); you can drag and drop the rules → Ok

You need to make your local network a trusted zone.

First look up your IP address and subnet mask. In Windows go to Start → Run → cmd → enter → ipconfig → enter → now lookup your IP address and subnet mask.

Second create a zone in My Network Zones (Firewall → Network Security policy). Choose Add → A New Network Zone → fill in a name like My local network → Apply. Now select My Local Network Zone → Add → A new address → choose An IP Address Mask → fill in your local IP something like 192.168.1.x usually and your subnet mask; usually → Apply. Now check and see the new network defined. Exit using Apply.

Now we are going to use the Stealth Ports Wizard to make your local network a trusted network:
Choose “Define a new trusted network and stealth my ports to EVERYONE else” → Next → choose “I would like to trust an existing My Network Zone” → choose your local network zone from the drop down box at the bottom → Finish.

Now check your Global Rules and see your network added.
(Mod edit: the above is not relevant for this problem. Hence, I made it smaller.)

Can you also tell me what game you play becasue there is an easier way to allow an online game to get the port it needs.

Valentin N