eMule relies on two parallel networks to function: the eD2k network, structured around central servers, and the decentralized Kad network. The quality of your eD2k server list directly affects your connection speed, the number of sources found, and, most importantly, your security. Using outdated or unverified servers exposes you to spy nodes, corrupted files, and faulty IP filtering.
server.met file and eD2k discovery mechanism
The eMule client stores its server list in a file named server.met, which is read at startup. This file contains the IP address, port, name, and various metadata of each server. When you connect to an eD2k server, it can pass you other server addresses, which automatically feeds your list.
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This propagation mechanism poses a concrete problem: fraudulent servers can inject themselves into your list without any action on your part. That’s why most guides recommend disabling the automatic list update when connecting to a server or client. The option can be found in the client preferences, under the Server tab.
A point often overlooked: the procedure for configuring and adding eMule servers described for the Windows client applies almost identically to aMule, the open-source port for Linux and macOS. The aMule project takes the source code from eMule, and new features are generally integrated shortly after being added to the official client. The server.met format remains the same, as do the URLs for reliable lists.
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TCP and UDP ports: opening the right accesses on your router
eMule uses two main ports: a TCP port for data transfer and a UDP port for search queries and communication with the Kad network. By default, the client proposes random values upon first installation. You can modify them in the preferences, under the Connection section.
For the client to obtain a “High ID,” these two ports must be accessible from the outside. A Low ID severely limits the number of available sources and slows down transfers. Three steps are necessary:
- Open the chosen TCP port in your router or internet box’s port forwarding rules, pointing to your machine’s local IP address.
- Open the corresponding UDP port in the same manner. eMule displays both numbers in its preferences, under the Connection section.
- Ensure that your system’s software firewall (Windows Defender, iptables on Linux) allows incoming and outgoing traffic on these two ports for the eMule or aMule process.
Once the ports are correctly forwarded, restart eMule. The connection icon in the lower bar should display a green arrow, indicating a high ID. If you see a yellow or red arrow, the TCP port is not reachable from the outside.
Kad network and eD2k servers: two complementary layers
The Kad network does not rely on any central server. Each Kad client acts as a node in the network, making it more resilient to failures and surveillance attempts. However, Kad alone is not always sufficient for quickly locating rare sources.
The eD2k servers maintain a centralized index of files shared by connected clients. This centralization allows for faster searches on specific keywords. The combination of both networks offers the best source discovery rate.
To activate Kad, you need an up-to-date nodes.dat file, downloadable from the same community sources as the server lists. This file should be placed in the eMule (or aMule) configuration folder. Upon first launch, Kad performs a “bootstrap” that can take several minutes before finding enough nodes.
When to favor one over the other
If you are looking for a very specific file with an exact name, an eD2k search via a reliable server will yield more targeted results. For widely shared files, Kad often finds more sources in the long term. The best practice is to keep both networks active at all times.
IP filtering and fraudulent servers: what the lists don’t tell you
Lists of “reliable” servers circulate on a few reference sites in the form of URLs pointing to a server.met file. Adding this URL in eMule’s preferences (Server tab, “Update list from URL” field) and then clicking the update button replaces the local list with that of the remote file.
IP filtering adds an extra layer of protection. eMule can load an ipfilter.dat file that blocks address ranges known to host spy servers or malicious clients. This file is regularly updated from community sources, and its absence exposes you to nodes that collect search queries.
A fraudulent server does not just slow down your downloads. It can return falsified results, redirect to infected files, or log all your queries. IP filtering does not guarantee total protection, but it significantly reduces the attack surface.
Manually checking a server’s integrity
Before manually adding a server (via its IP and port), check that its name and address match those published on recognized community sites. A server whose name changes frequently or whose UDP port does not respond to status requests should be removed from the list.
Legal status of P2P in 2026: a persistent gray area around clients
Recent European regulations focus on platforms and digital intermediaries: hosts, marketplaces, streaming services. P2P clients like eMule, which do not store anything centrally, remain in a legally ambiguous status in Europe. The tool itself is legal. It is the usage that determines legality: sharing copyright-free files or content under open licenses poses no problem.
The available data does not allow us to conclude that this gray area will evolve in the short term. Authorities are focusing on centralized infrastructures rather than decentralized protocols. Properly configuring your servers, enabling IP filtering, and using Kad does not change the user’s responsibility regarding the content they share or download.
The longevity of eMule is due to its community and the lack of equivalent alternatives for certain rare or old content. Maintaining a clean server list, properly opened ports, and active IP filtering remains the foundation for using this client under correct conditions, regardless of the operating system.