Eish…. Q fdp de blog Porque as ideias são para partilhar

May 15, 2008

O guia para empalar o teu operador de internet…

Filed under: P2P — xupetas @ 3:39 pm

Este é um artigo escrito pelo Tom Spring, na pcworld. Sei o que vão pensar… pcworld…. mas não deixa de ser muito interressante.

Vai ao encontro do que se tem falado sobre os PUAS, TS, e afins…. muito interessante mesmo.

Link original

I’m a fan of live music and a patron of online communities such as eTree.org, where music junkies swap copyright-free music. So I was stung when I recently tried to download a live recording of a Dave Matthews concert only to discover that my BitTorrent client was dead in the water.

My system and Net connection checked out fine, so paranoia immediately set in: Was my Internet service provider, RCN, blocking BitTorrent? I called RCN and the tech I spoke to confirmed my suspicions, telling me that the ISP had added BitTorrent to its list of prohibited programs because many people use the software to download copyrighted material. The fact that the concert I was trying to download was copyright-free didn’t sway him.

Later I called RCN’s press department as a reporter, and the story changed. The ISP’s spokesperson told me that the customer support rep I had talked to earlier misspoke. RCN has never intentionally blocked peer-to-peer traffic, the spokesperson said, and it supports the principles behind Net neutrality. Within 24 hours, my bandwidth-related problems with BitTorrent vanished.

Of course, most people can’t call their ISP and (honestly) identify themselves as professional journalists. But that doesn’t mean you have no recourse if your ISP starts blocking your file-sharing activities. A number of tips and tools can help you determine whether you’re facing a BitTorrent blockade and, if so, help you get around it.

Torrent to a Trickle

If you suspect that your ISP is blocking or throttling your BitTorrent traffic, call your ISP and ask whether you’re being blocked. But don’t trust that you’ll get a straight answer.

If your ISP’s support reps won’t tell you what’s going on, look at the company’s terms-of-service agreement (most are available online). Here again, though, you may find the answer unsatisfactory. Some ISPs couch their bandwidth management practices in vague policy statements that are difficult to decipher.

If your ISP won’t come clean about its BitTorrent bandwidth policy, you can try any of a handful of ways to test whether your BitTorrent traffic is being throttled.

One method is to test your own connection speed. BitTorrent download speeds for popular files with many sources should be in the same ballpark as your bandwidth speeds in benchmark test results.

A popular Web-based tool, Glasnost, claims to be able to check whether your ISP is meddling with your BitTorrent traffic. The tool, created by the Max Planck Institute for Software Systems, requires no download; performing the test takes about 4 to 7 minutes.

For diehard techies who are willing to tinker, the Electronic Frontier Foundation developed a tool called Pcapdiff that tests whether your ISP is disrupting BitTorrent traffic.

Last, the makers of the BitTorrent client Vuze have created a plug-in for their peer-to-peer file swapping client. Downloading and running it on your PC won’t help you determine whether your ISP is meddling with BitTorrent traffic — but it will help Vuze, which uses the data to lobby the FCC to prohibit limitations on BitTorrent.

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. One of these techniques may work for one ISP but not for another.

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 will step you through the process of tweaking your router to permit incoming connections.

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 $US5 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.

Xupetas

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