Firewall Setup

Many people are using firewalls or proxies these days to increase the security of their computer systems. Generally, CDC32 is compatible with most home routers and firewalls. In most cases, CDC32 can either setup your router to accept direct calls, or use protocols that will work if it cannot setup your router. See below for cases where this might not work.

In a typical home network, there are two things to look out for: (1) A router, which is something you connect multiple computers to in order to share one internet connection; (2) A firewall, usually a personal firewall, which is running on the same computer that is running CDC32.

Personal firewalls:

Zonealarm, SunBelt Personal Firewall, and others of the same ilk: these programs normally ASK you if you want to allow "Dwyco CDC32" to access the internet, and become a server. If you answer yes (and check the "remember this program" option), your problems will be solved. If your pal list still doesn't show users in red when they come online, then you may have to try setting the firewall to "medium" security mode. If things STILL DON'T work, try turning your firewall off altogether to see if that is the problem. If things still don't work with your personal firewall off, then you have another problem somewhere.

If you are using a DSL or CABLE ROUTER you can either:

Do nothing. CDC32 can usually setup your router. This is the easiest method. This is recommended unless you are an expert and want maximal performance from CDC32.
Add your computer's IP address to the DMZ on the router. Consult your router's documentation for how to do this. You will also want to be running a personal firewall on your machine if you do this. See the setup above for how to deal with that. This is the best option for ease of use, as it will appear that your computer is directly connected to the internet, and all of cdc32's functionality will work.
Forward specific port ranges from the outside of the router to your IP address internally (normally you will not have to specifically forward anything for the other direction, the router will handle that properly without your intervention UNLESS you have specifically set your router to filter outgoing connections.)

TCP ports: incoming 6780 for making direct connections to other CDC32's
TCP ports: 1024-5000 for file transfers and direct video zaps and calls.

If CDC32 cannot make a direct connection with TCP, it will attempt to connect to the remote party with the assistance of the Dwyco servers. In this case, CDC32 may attempt to use UDP to transfer audio and video data directly between the computers in the call. The UDP ports used are essentially random, though most home routers will not need special setup to allow this kind of traffic (there are routers that cdc32 simply cannot exchange media with, but thankfully those should be rare.)

Known, (but thankfully infrequent) problems:

Some people use ISP's that filter out UDP for "security reasons". CDC32 does not have specific features for finding and using complicated proxies. However, most firewalls and proxies can be configured to allow CDC32 to work transparently. If you completely turn off your firewall (for testing purposes), and you still can't get CDC32 to connect, you may have to call your ISP to ask whether they perform some kind of filtering for you.
Some routers filter out all UDP traffic packets over a certain size (usually around 8192 bytes). The only method around this is to reduce the size of your video to 160x120, which usually results in small enough packets that the problem goes away. If you know your router has problems with UDP, you can also force CDC32 to use TCP only in Setup|Ports/UPnP...