ID is a value calculated from the client's IP address. It is assigned by the server, when eMule successfully connects. The purpose of the ID is to give an indication whether or not proper communication is possible between two clients.

After connecting the ID is displayed in the Server's Log window.

eMule does not display the ID any further but does show the ID status graphically as colored arrows on the globe in the lower-right corner, next to the connected server.

indicates a high ID in all networks
indicates a low ID in all networks

For a more detailed overview, see the Icons page.

A high ID means the port chosen in Options -> Connections (default 4662) is open and freely accessible, whereas a low ID means this port is blocked or cannot be reached. This can be caused by firewalls, routers or proxy servers. Having a low ID does not mean that no up- or download is possible but has several disadvantages:

• No IP is known of the machine eMule is running on therefore all requests like queue or connection requests to this client have to be routed over the server, the low ID client is connected to. This routing causes considerable amount of CPU load on the server thus reducing the maximum number of users the server can cope with. Lugdunum's servers limit the number low ID users or even ban them at all.
• Two clients on low ID cannot connect to each other, as it is not possible to route messages over two different servers. This will lead to less sources for the downloads
• On busy servers it may well happen that the messages get lost and eMule misses important information about queue progression or download requests. This may lead to fewer credits and worse downloads.

Notes:

1. The ID issue only affects message exchange between clients. Actual data transfer is still handled client to client.
2. If it is not possible to get a high ID, it is better to connect to low user servers as they have more resources left to deal with it than the big congested ones.
3. You can also get a low ID when the server you connected to, is too busy to answer properly, or simply badly configured. When you are sure your settings are ok and you should have a high ID, connect to another server. Run eMule and use the Port Tester from Options -> Connections to check if your connection is set up properly.
4. If the ID is high, it does not matter how high it is. An "even higher" ID is not better nor does it offer any advantages.
5. If an ID is low, it does not matter how low it is. A low ID is any value less than 16777216.
6. To convert from a High ID to an IP, use the following: for IP = A.B.C.D the High ID = A + 256*B + 256*256*C + 256*256*256*D.
7. Important: Since .23a low ID sources are dropped by eMule to keep load on servers to a minimum. Only low ID sources connected to the same server your client is connected to and low ID sources who want to download a file from you are accepted. Also low ID sources are not traded via Client to Client Source Exchange.