Troubleshooting Network Problems

Often when 2 computers cannot communicate it is due to some type of network configuration issue. Intercom relies on UDP, and specifically UDP broadcasts to operate. Typically home and office network configurations allow for this type of network communication, so it should "just work".

However, when it does not "just work" there are many variables involved which can be specific to your hardware and firmware version. For an example, one type of problem can occur when some computers are on a wired network and some are on the wireless (Wi-fi) segment. See this article for further information: Why do some WiFi routers block multicast packets going from wired to wireless?.


Step 1: Turn off all firewalls and anti-virus

Firewalls and anti-virus can interfere by blocking the ability for Intercom to communicate. To see if these are responsible, disable these components and see if Intercom works after that. Note that on Windows, the built-in firewall should be configured automatically. However 3rd party firewalls will need to be configured separately.



Step 2: Test network connectivity between 2 endpoints

You can test whether or not your network supports UDP broadcasts between 2 points by using the free utility Packet Sender for Mac or Windows which will allow you to test UDP connectivity between 2 computers. If you can verify Packet Sender can communicate between your two computers, then you have verified that your network supports the requirements needed by Intercom.

  • Install and start the Packet Sender application on both computers
  • Update the fields as seen below:
    • ASCII set to "Hello World"
    • IP Address set to the other computer's IP address (which can be found in the title bar of Intercom)
    • set Port to 55056
    • set the dropdown to UDP
  • Click Send. Now look at Packet Sender on the other computer. You should see the message appear in the Log area at the bottom if directed UDP traffic is making it between the 2 computers.
  • Next, at the first computer update the IP Address field to 255.255.255.255 (the broadcast address) and try sending again. The other computer should get this message also. This verifies that broadcast messages are working.
  • If UDP does not work, try switching to TCP and see if that works.
  • Try switching computers so the other computer is now the sender. Ensure that works also. Sometimes it will work one direction but not the other.
  • If broadcast UDP is not working between the 2 computers, you will need to figure out how to enable this for your specific computer/3rd party software/network hardware configuration. It is not possible to provide exact instructions because there are so many possible configurations, but you might be able to get one of your geek friends to help you get it working. Just tell them that you need to get UDP broadcasts working between the two computers on your network. You may find better success if instead of asking directly, you pose it as a challenge. Geeks love to be challenged: "You know, nobody can seem to solve my problem with UDP broadcasts on my home network."