It's how long archeology has said we have had permanent settlements.
In reality it's likely far earlier than that, we only just found a settlement from 11,000 BCE in Turkey, Gobekli Tepe which was likely a sanctuary/shrine, as well as other towns in the surrounding area likely having started before even then.
Big archeology pushed back to say that that's not 100% certain and that humans were still nomadic, despite all the evidence showing otherwise. It was finally just recognized officially a couple months ago.
It's usually in the network settings of the torrent client. Usually listed with "IP interface binding" or some such.
Qbittorrent has it as a dropdown menu with a list of available IP's to use, as well as an option to set it manually.