Increase download speed of a BitTorrent client

Some users of the BitTorrent client report experiencing slow downloads when sharing P2P files. This is most likely to occur on computers behind a home router or software firewall.

Being behind firewalls, the BitTorrent client may block incoming Bit Torrent network connections. Given the load balancing and "swarming" nature of the BitTorrent network, clients unable to take incoming requests for uploads will naturally be allowed less bandwidth for downloads.

To solve this problem, consider the following:

• When a user starts a BitTorrent client, the client sets up a network resource called a "port" to allow other Bit Torrent clients to connect ot it. Each port possesses a unique number called the "TCP port number."
  
  
• A BitTorrent client normally associates the TCP port number 6881. However, if this port is busy for some reason, the client will instead try successively higher ports (6882, 6883, and so on up to a limit of 6999). In order for outside BitTorrent clients to reach this one, they must be able to connect to the correct port.
  
  
• When connecting to another BitTorrent client, the requesting client will first try port 6881, then 6882, and so on. However, if the computer is on a firewalled network, the incoming request may not reach these ports. On the other hand, if these requests succeed, the accepting client will be able to download faster.
  
  
• Firewalls can block nearly all of the ports used by P2P clients. To ensure the BitTorrent ports are made available to requesting clients, a home router or firewall can be manually configured to accept them. Most home routers possess a feature called "Port Range Forwarding" to do this. This feature allows the administer to tell the firewall where traffic for a given port number should be directed.
  
  
• For BitTorrent, many home users set up port forwarding on the TCP range 6881-6889. These ports must be directed to the computer running the BitTorrent client. If more than one computer on the network may run BitTorrent, a different range such as 6890-6899 or 6990-6999 can be used for each. Remember that BitTorrent uses ports in the 6881-6999 only.
  
  
• Many people don't realize that Windows XP computers include the built in Windows Firewall. If port forwarding is set up on a home router, but Windows Firewall is running on the BitTorrent client computer, incoming requests may still fail to reach the client. Ensure the Windows Firewall is either disabled or is set up to allow the appropriate BitTorrent ports to pass through. The same recommendation applies to other software firewalls.
  
  
• On home networks without a router, the software firewall (Windows Firewall, ZoneAlarm, or other) must be set up to provide the equivalent forwarding or pass-through capability as needed.

via computernetwork