eDonkey2000 connects to both servers and the eDonkey network. Connecting to each network will be handled separately for clarity.

Connecting to the eDonkey Network:
Connecting to the eDonkey network is relatively simple. Your client requires a list of servers which it will attempt to connect to. While this is occurring you will see something like:
Trying to connect to 192.168.2.1
Unable to connect
Trying to connect to 127.0.0.42
unable to connect
Trying to connect to 10.25.32.12
Connecting
in the message window at the bottom of the screen. This is a good sign and is normal. Eventually you should see a server welcome message, and the eDonkey status will turn to Connected. If this seems to take an unseemly amount of time, you can download a new server list. To do this, open the Server tab, right click, select Get Server List, select a download location and hit OK. Then give the program a little more time with the updated server list.

Connecting to the eDonkey Network:
Connecting to the eDonkey Network should be even simpler. eDonkey comes with a list of other peers on the network. If even one of them is still active (very likely) it will connect and share a new set of peers.

Ensuring open communications:
While eDonkey is still running visit the connection tester, enter your TCP port and click test. It will attempt to connect to your eDonkey client. If it returns an error a firewall, gateway, router or other is blocking your connection to eDonkey. This could result in one of two things:
A) You will receive Firewalled status while connected to eDonkey, and may not be able to achieve full transfer speeds.
B) You will be unable to connect to the eDonkey network.

Try setting your TCP port to 80 in the Network Options. Visit the connection tester, again, entering 80 in the port box this time and click test again.
Hopefully this time it reports okay.

After another set of "Trying to connect" Cycles, it should connect to a server.

Still Having Problems: One problem could involve the type of connection given to you by your internet service provider. If you use a proxy for your web browsing or other internet activities, you may need to enter that information into the proxy section of eDonkey Options. If you are still receiving an error visit the help page for Firewalled users, it contains more information.