Firewall Settings for Popular IM and VoIP Services

Instant messaging isn’t just about text messaging…and hasn’t been for a long, long time. Today we can use AOL Instant Messenger (AIM), Windows Live Messenger, and Yahoo Messenger to share live webcam images, computer-to-computer voice conversations, and computer-to-phone calls. Adding to the diversity of our computers are Voice over IP (VoIP) applications such as Packet8, Skype, and ViaTalk for computer-to-computer, computer-to-phone, and phone-to-computer calls. Computer-based phone service is a relatively new but increasingly popular means to connect to the huge domestic and international phone systems, or simply chat between PCs.

In most cases of home networking, you won’t have to touch a thing—unless your software firewall prompts you to authorize a specific application to connect, or your application requires an inbound connection, which are usually blocked by both hardware and software firewalls. It is when things do not work that you have to find out what your applications and services need and dig into your firewalls and open things up.

Firewall Settings for Yahoo Messenger, Webcam, and Voice Services:

Yahoo Messenger text messaging automatically uses TCP port 5050, but can function on port 80 or 443. The webcam sharing feature uses TCP port 5100. Yahoo Voice Chat uses TCP or UDP ports 5000–5010. Yahoo Voice service uses TCP ports 20, 23, 25, 80, 119, 5050, 8001, and 8002. The Yahoo Messenger client does not allow you to change any of these settings to work around proxy server or firewall restrictions, but it does allow you to change its configuration to suit a proxy server (common in most corporate networks) or firewall.

To access the Yahoo Messenger Preferences window, choose Messenger | Preferences | Connection.

If Yahoo Messenger does not work, your options are to configure proxy server settings if you know there is a proxy server between your computers and the Internet (mostly at work, rarely at home) or configure your firewall to allow access for the ports needed.

Firewall Settings for AIM

AIM’s settings are about as simple as you can get: it offers no network configuration settings—it simply figures out the best port to use on its own. It works well through proxy servers and firewalls, preferring to use TCP ports 5190–5193, but basic text messaging is also known to use ports 23 and 80 in a pinch.

Firewall Settings for Microsoft Live Messenger

Live Messenger can be configured to work through a firewall, as shown in the illustration below, but that is all you have available to configure to get it to work. If you find that you need to configure your firewall to allow Live Messenger to make outbound connections or accept inbound connections, with all of the ports used by all of the available features, you’ll be pretty busy.

The text chat feature prefers TCP port 1863, but is known to function on ports 80, 443, 1493, 1542, and 1963. The file transfer/sharing feature uses TCP ports 1544 and 6891. Remote Assistance uses TCP port 3389. Audio chat uses TCP ports 1556, 11771, and 13803 as well as UDP ports 5004–65535. The Remote Desktop and whiteboard features use TCP ports 389, 522, 1503, 1720, and 1731. Launching games uses TCP port 80. The video conference feature uses TCP ports 9000–9999 and UDP ports 5004–65535. Signing in uses TCP port 443.

Firewall Settings for Skype

Skype is one of the most popular stand-alone VoIP programs and provides a good example of the typical network configuration for making Internet and normal phone calls from your computer. The only configuration option you have for Skype is the port to be used for inbound call requests from others, as shown below;

You can access the network configuration in Skype by choosing Tools | Options | Connection. If the Skype service cannot connect on this randomly assigned (at time of installation) port, it will try ports 80 and 443. If you open the indicated port number, or another of your choice, on your firewall, Skype should be able to use it for inbound calls.

Skype is flexible and effective but recommends opening both outgoing and incoming UDP ports above 1024 (1024–65536). Skype will work through a proxy server, and uses the proxy settings, if any, that have been configured in Internet Explorer.

Firewall Settings for Packet8

Packet8 uses several outbound UDP ports, 5060–65534. Few if any hardware firewalls

restrict outbound connections—anticipating that you want to make these connections—but software firewalls may be suspicious of outbound connections they do not “know” about. If you use a software firewall, and Packet8 fails to work, you need to configure your firewall to allow the outbound UDP connections for the port range 5060–65534. Packet8 does not request inbound connections, so no configuration to accommodate these is necessary.

Firewall Settings for ViaTalk

ViaTalk seems to use a broad mix of ports for its VoIP services, all of which require inbound connections or port-forwarding to the computer running the ViaTalk client. In addition to normal web TCP port 80 outbound connections, ViaTalk requires inbound UDP configuration for ports 69, 5060, 5061, and 10000 to 20000.

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