Videoconferencing for Linux

FIREWALL SETUP

Modern distributions usually use ipchains. You can update the various files that configure ipchains by simply running the script from here in section 6.2 entitled "What iptables rules could I use for GNU/Linux?" Cut and paste the script into the text editor of your choice. Save it as ekiga-iptables-setup.sh anywhere convenient.

Note: Do not run it until you've changed ppp0 in the line

EXTERNAL_DEVICE="ppp0"

...to whatever actually matches your system. Of course, if you're running dialup, ppp0 is probably right. But dial-up users are a shrinking minority. The script should now be running eth0 by default, and it should have a comment line showing what's most likely to be changed. In most cases, you'll want to change that line to eth0 as follows:

EXTERNAL_DEVICE="eth0"

Run it by:

# sh ekiga-iptables-setup.sh 

If you don't know what your EXTERNAL_DEVICE is, run:

# ifconfig

Ignore lo, and if you're running VMware Server, all vmnet* entries, it's the connection to the Net you're looking for.

ROUTER SETUP

Go to your router setup page. (Read the instructions. It's usually a webpage accessible via browser.) If it has a setup for H.323, SIP, stun, or videoconferencing, click the checkbox or enable the menu setting, and you're probably done. If it doesn't have the setup, go ahead and start running the Ekiga Configuration Druid.

If you haven't done so already, plug the camera into the USB port. Also, plug in whatever microphone device you plan to use if you don't plan to use the microphone built into the camera.

Open Ekiga from the menu. top menu > Edit > Configuration Druid I regard the UserID and related account info screen as self-explanatory. Click on "Get an Ekiga.net SIP Account". It'll open a Web browser; do the obvious. Concerning the following two screenshots: Though they're similar in appearance, they do have important differences. Specifically, while both figures are of the fifth frame of the Ekiga videoconferencing setup wizard, the first figure shows "Cone NAT" setup and STUN ready to go (which is correct). The figure after that shows "Symmetric NAT." All of which means you'll have some router setup work to do. So here's a screenshot of what the Ekiga setup wizard does when you're ready for videoconferencing:
If you see that, then your router is probably configured correctly. Click Yes and Forward. Skip the images showing router configuration here down to Video Codecs. The following figure shows what appears when there's a NAT-detection problem:
If you see this, then your router setup is either incomplete or wrong. "Symmetric" in this context means that the router won't respond to an incoming message unless this port has already been opened from inside the LAN. While that may be a good security practice, it is not so good when you're trying to get an incoming call behind a router that can't hear it.

The following is the setup on my Airport 101 AR420W wireless router. (the "wireless" part is irrelevant here). In general, these routers are set up via a set of Web pages resident within the router accessible via an ordinary browser. For documentation on your specific router, check for the manual that came with it, either on paper or on the disk that came with it. (usually Adobe Acrobat PDF format). Here's a shot of the port forwarding settings:

SIP port forwarding:

ports: 3478-3479 (labeled stun-voip1 above)
ports 5000-5100 (labeled stun-voip1 above)

Here's a screenshot of port range triggering setup:
The port triggering is because the original "Symmetric NAT" test result says that the router won't ordinarily open a port unless a computer on the LAN behind the router first accesses it. So to respond to an incoming request, it has to have ports configured specifically to accept them. This is called port-range triggering. Set port triggering for:

Ports triggered: 3478-3479
Ports Forwarded: 3478-3479
Ports triggered: 3478-3479
Ports Forwarded: 5000-5100

Hit "Apply," "Enable," or whatever is appropriate for your router. Then repeat the Ekiga Configuration Druid. You should see the image above labeled "correct configuration." Go on to the next step, and select ALSA as the first choice. Here's a shot of the audio driver screen:

The audio device can be any microphone device you can plug into your PC, including microphones plugged into the audio input. In the picture above, I'm using the microphone built into my digicam and getting it via the same USB connection that provides video. If you can't hear anything, check the volume controls. Make sure the appropriate I/Os are switched on and that the input / output volumes are at a reasonable level. If that fails, go back a step and try changing ALSA to OSS.

Next, you'll be asked to select the Video Manager. Pick the one (either V4L or V4L2) that matches your camera type. Try V4L if you don't know. On the next step, select your camera device. Simply pull down the menu below "Please choose your video input device" and select the entry that matches your camera. After that, you should see this configuration-complete screen:

Now you are ready to test Ekiga. If you need to change the device data later, you can do this from Main Menu > Tools > Preferences. The videophone test screen looks like this:

Making a test call:

sip:500@ekiga.net

This is the ekiga.net echo test number. I recommend using "side by side" video (View > Side-by-Side) to let you see what your video looks like from the other end. You can also dial username@ekiga.net if you know the username. To let you see what you're sending out, you can put the image into side-by-side mode by going to the main menu and pulling down Tools > Side-by-Side. The image to the left is the remote image, the right is local.