Evasion of the Bit Snatchers
If you discover or strongly suspect that your ISP is slowing your BitTorrent traffic, you can try several countermeasures, none of them a sure bet.
First, try using encryption to cloak your peer-to-peer traffic. Most clients such as BitComet, BitTorrent, uTorrent, and Vuze, support in-client encryption. Turning this feature on makes it much harder, though not impossible, for your ISP to detect that you're using peer-to-peer software. Here's how to proceed.
BitComet: Go to the Options menu, choose Preferences, Advanced, Connection, and select Protocol encryption.
BitTorrent and uTorrent: Go to the Preferences panel and select the BitTorrent tab. Choose Protocol encryption and select enabled.
Vuze: First you must change your user profile from the default beginner mode to advanced. Go to the Tools drop-down menu, open the Configuration Wizard, and select advanced. Next return to the Tools drop down menu and select Options, Connection, Transport Encryption. Check Require encrypted transport, go to the Minimum encryption drop-down menu, and select RC4 encryption.
A second method of evading an ISP's throttling practices is to change the way the BitTorrent protocol acts. This method may work against ISPs that try to throttle speeds based on a standard set of BitTorrent configurations.
Troubleshooting your BitTorrent client's protocol settings can be tricky. To reconfigure your software, refer to the instructions provided by the publisher of the BitTorrent client you're using. One simple yet effective way to experiment with alternate BitTorrent protocol configurations is to simply try a different BitTorrent client. Different clients use different default protocols, and one may perform better on your ISP's network.
The default communications port used by BitTorrent traffic is 6881. ISPs know this and watch that port like a hawk. If an ISP throttles or blocks BitTorrent traffic traveling through this port, your file-sharing speeds will plummet.
To elude ISP throttling, BitTorrent clients enable you to switch the port or port range that your computer uses for BitTorrent traffic. Some BitTorrent clients will automatically attempt to configure your firewall or router to allow traffic to pass through the new port; with others you may have to open ports on your router manually. The excellent Port Forward site
One more-advanced method of obfuscating your BitTorrent traffic involves using an encrypted tunnel that, as the name suggests, shields from your ISP the type of data you are sending and receiving.
Free services such as The Onion Router (TOR) and I2P are designed for sending anonymous and encrypted messages, but some people have adapted them to use BitTorrent connections. The Vuze client has built-in support for routing your traffic through TOR and I2P.
For about $5 a month, commercial virtual private network providers such as Relakks and SecureIX can help you prevent your ISP from identifying BitTorrent traffic. In marketing its service, SecureIX promises that it will "disable P2P throttling." The company offers a free tier of service with a bandwidth limit set to 256 kbps.
But ISPs are catching on to these advanced encryption techniques, reportedly clamping down and throttling encrypted tunnels despite being unsure that the encrypted data is BitTorrent traffic. The most extreme method an ISP may use to manage peer-to-peer traffic is to block anything that appears to be BitTorrent traffic, encrypted or not. If that happens to you, you must either switch ISPs or stop using BitTorrent software.