when I use a magnet link to download file, where am I actually download it from
When you use a magnet link to download a file, you are downloading it from other users who are also downloading and sharing the file on the BitTorrent network. When you open the magnet link, your computer connects to a tracker, which helps to coordinate the download and upload of the file among all of the users who are participating in the file sharing. The tracker does not actually have the file itself, but rather it keeps track of which pieces of the file are available from which users and helps to facilitate the transfer of the file from one user to another. When you download the file using a magnet link, your computer is connecting to and downloading pieces of the file from multiple users on the network, rather than from a single source.
then who build the tracker?
There is no single entity or group of individuals that builds and maintains all of the trackers on the BitTorrent network. Instead, trackers are operated by a variety of different organizations and individuals, and there are many different trackers available for users to choose from. Some trackers are operated by private organizations or individuals and may be invite-only or require users to pay a fee to access them. Other trackers are operated by public organizations or volunteers and are available for anyone to use. Some common types of trackers include private trackers, public trackers, and distributed hash table (DHT) trackers.
How does my BitTorrent software know where to connect to the tracker
When you open a magnet link or torrent file, your BitTorrent client software reads the metadata contained within the link or file to determine which tracker it should connect to and which file or files it should download. The metadata includes the address of the tracker, as well as a list of hashes that are used to identify the file or files that are being shared. When your BitTorrent client establishes a connection with the tracker, it sends a request for the file or files that are identified by the hashes in the metadata. The tracker responds by providing a list of other users who have the file or files and are willing to share them, and the BitTorrent client begins downloading pieces of the file from those users. The client also communicates with the tracker periodically to update it on the status of the download and to request additional pieces of the file as needed.
How does my software share or upload file to others?
When you use a BitTorrent client to download a file, the client also uploads (or seeds) the file to other users who are downloading the same file. As the client downloads pieces of the file from different users, it also makes those pieces available to other users who are downloading the file. This helps to distribute the load of transferring the file across multiple users, rather than having a single source serve the entire file to every user who wants to download it.
The BitTorrent protocol is designed to encourage sharing by rewarding users who upload more with faster download speeds. This means that the more you seed a file, the faster your own downloads will be. Some BitTorrent clients even have features that allow you to specify a maximum upload rate, so that you can limit the amount of bandwidth that the client uses for uploading and potentially free up more of your own internet connection for other tasks.
You said if I shared more, I can get faster download speed. But how am I being indentified so that the protocal give me faster speed when I shared more.
When you use a BitTorrent client to download a file, the client establishes a connection with the tracker, which assigns you a unique identifier known as a peer ID. Your peer ID is used to identify you to other users on the network, and it allows the tracker to keep track of your contribution to the file sharing.
As you download and upload pieces of the file, your BitTorrent client sends and receives messages with other clients to coordinate the transfer of data. These messages include information about your peer ID, as well as the number of pieces of the file that you have downloaded and uploaded. The other clients and the tracker use this information to determine how much you have contributed to the file sharing and how fast your download speed should be.
In general, the more you seed a file (i.e., the more you upload), the more you will be rewarded with faster download speeds. This is because the BitTorrent protocol is designed to encourage sharing by rewarding users who contribute more to the file sharing with faster download speeds. However, the exact details of how this works can vary depending on the specific implementation of the BitTorrent protocol and the settings of the tracker and the clients.
Where is my peer ID stored?
Your peer ID is usually stored in the configuration file of your BitTorrent client software. It is also included in the messages that your client sends to other clients and to the tracker when you are participating in a file sharing session. Your peer ID is a unique identifier that is used to identify you on the BitTorrent network, and it is typically a string of letters and numbers that is generated by your client when you first install it. The exact format of the peer ID can vary depending on the specific BitTorrent client that you are using.
In general, your peer ID is not tied to your personal identity or any other identifying information. It is simply a unique identifier that is used to distinguish you from other users on the network. However, it is possible for someone to potentially use your peer ID and other information that is exchanged during a file sharing session (such as your IP address) to try to determine your identity or location. For this reason, it is a good idea to use a VPN or other privacy protection measures when using BitTorrent.
What if I shared a lot files with a tracker, but I want to download a file that connect me to another tracker, how does the new tracker know my contribution? I mean this new tracker may not know my peer ID
When you use a BitTorrent client to download a file from a new tracker, the tracker will not have any information about your previous file sharing activity on other trackers. Each tracker maintains its own database of information about the users who are connected to it and the files that are being shared, and this information is not shared between trackers.
However, your BitTorrent client will still include your peer ID in the messages that it sends to the new tracker, and the tracker can use this information to identify you and track your contribution to the file sharing for the current session. The tracker will also keep track of the number of pieces of the file that you have downloaded and uploaded, as well as your upload and download speeds, and it will use this information to determine how fast your download speed should be.
It is worth noting that some private trackers may have arrangements in place with other private trackers to share information about their users’ file sharing activity. In these cases, it is possible that your contribution on one tracker may be recognized on another tracker that is part of the same network. However, this is not something that is done by all trackers, and it is not something that is controlled by the BitTorrent protocol itself.