or whose IP address ends with a zero (e.g. 123.45.67.0) get a "Low ID" from the servers. They are still able to upload and download but need the help of servers or other kad clients to be reached by other clients. Since they cannot be notified that they are in front of an upload queue, they have to poll peers if an upload slot is available. Since they cannot connect to any other Low ID clients, they see only 40–60% of the clients that a High ID can see. Their IP/ports are not exchanged between other peers, limiting their possibilities for finding sources via eMule's pure-P2P source exchange. A Low ID client also consumes a lot more data on an eserver than a High ID client due to the lowidcallbacks. Also, a releaser or heavy uploader that uses a releaser mod such as MorphXT or Xtreme that is forced to operate on a Low ID (hotel room, job) also will find that they will have little control over their upload priorities (especially powershares) as the servers appear to limit their connection-forwarding for each client, thus turning their upload queue to a contention situation where the first to be able to get forwarding and find an open slot gets it. Credit system Credits are not global; they are exchanged between two specific clients. The credit system is used to reward users contributing to the network, i.e. uploading to other clients. The strict queue system in eMule is based on the waiting time a user has spent in the queue. The credit system provides a major modifier to this waiting time by taking the upload and download between the two clients into consideration. The more a user uploads to a client the faster they advance in this client's queue. The modifiers are calculated from the amount of transferred data between the two clients. The values used can be seen in the client's details dialog. To view this information, right-click on any user and choose View Details. All Clients uploading to you are rewarded by the credit system. It does not matter if the client supports the credit system or not. Non-supporting clients will grant you no credits when you upload to them. Credits are stored in the clients.met file. The unique user hash is used to identify the client. Your own credits are saved by the client who owes you the credit.