Why Can't Block BitTorrent Ports on Router?

Can you block or slow down the BitTorrent traffic on the router? This is a problem we have encountered many times. Others who use BitTorrent on the web may slow down your connection and even expose you to lawsuits. Unfortunately, there is no easy solution.
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Stop any difficulties

It is difficult to block anything at the home router level. Of course, if your router has parental control or other built-in website blacklist functions, you can block individual websites. If you don't want anyone to visit Facebook on your network, you can block facebook.com. But this problem can be solved through VPN and proxy.

BitTorrent is more difficult. This is not only to block a single website, but also a specific protocol used by computers on the network to communicate with other computers around the world. You can block any kind of traffic without a flick, but BitTorrent continues to evolve to make it more difficult.

BitTorrent avoids blocking and restrictions

The BitTorrent protocol has a goal for most of its history. Even Internet service providers like Comcast have gone to great lengths to limit BitTorrent traffic, thereby reducing the speed of their clients' agreements. Therefore, it is not surprising that BitTorrent has gradually evolved to be more difficult to stop and throttle. These tips that help BitTorrent evade ISP restrictions will also help it avoid blocking your home network.

You can’t just block the BitTorrent port

Why you can't block BitTorrent on your router

When BitTorrent was first released in 2001, the standard ports it ran on were TCP ports 6881 to 6889. Internet service providers and other network providers became popular. Many people started to use these ports to limit (slow down) all traffic. Some BitTorrent trackers have banned BitTorrent clients that use these ports from connecting because these clients may reduce the overall download speed of the group.

Even in those days, anyone can change the port used by their BitTorrent client to another port, thus evading the ban. Now it's more difficult. Modern BitTorrent clients often have built-in options to use random ports, which helps to evade detection.

Most importantly, modern BitTorrent clients use an extension called DHT ("Distributed Hash Table"), which means they don't even need to rely on a centralized tracker that can be blocked, they can be in a peer-to-peer network Exchange information. Peer fashion. When using DHT, the BitTorrent client communicates via UDP, negotiates and uses a different port for each connection.

And, although you can disable UPnP on the router to prevent BitTorrent clients from automatically forwarding ports to allow incoming connections, they can still establish outgoing connections.

You cannot use traffic inspection due to encryption

Why you can't block BitTorrent on your router

Faced with most BitTorrent clients that no longer run on predictable ports, ISPs and other network operators turned to a method called "deep packet inspection." They can inspect all network packets specific to BitTorrent traffic characteristics, identify those packets associated with BitTorrent, and throttle or block them.

Not surprisingly, this has caused the BitTorrent protocol to add another feature: encryption. This may be called Protocol Encryption (PE) or Protocol Header Encryption (PHE), depending on the BitTorrent client you are using. The purpose of this is to "confuse" BitTorrent traffic, making it more difficult for ISPs and network operators to detect and shape BitTorrent traffic. In other words, it makes it difficult for ISPs to fix and slow down BitTorrent traffic.

Some routers have quality of service (QoS) features that try to identify the type of traffic and allow you to restrict traffic on the network. As you might expect, the confusion of BitTorrent's port and protocol encryption capabilities also prevents your home router from recognizing BitTorrent traffic.

How to stop (or slow down) BitTorrent on the network

Why you can't block BitTorrent on your router

In short, there is no simple technical solution. You will not find a one-click button that will disable or even reduce BitTorrent traffic on the entire home network.

Organizations do have some technical choices. Organizations that control their workstations can use the application whitelist feature to prevent employees from running BitTorrent clients on their PCs. Companies hosting public Wi-Fi networks can try to block everything except standard web browsing traffic.

At home, if someone can access your network, then they can do what they want. To get everyone out of the Wi-Fi network, just change their password, and only devices with the new password can connect. You can use MAC address filtering to block a specific device in the router, but this will block all connections to that device-BitTorrent and all other connections. People who use Wi-Fi passphrases can also solve this problem.

If your family or roommates will only increase the workload and make everything slow, we recommend skipping the technical solution and asking them to stop. If you are worried that they will reduce network speed, ask them to set upload and download speed limits in their BitTorrent client.

If you do have a router with quality of service features, it will not necessarily reduce BitTorrent traffic only. However, you can configure your router to prioritize all traffic from devices known as BitTorrenting and prioritize all traffic from other devices on the network that are easier to use. For more information, please consult your router's documentation.