Torrenting crashes internet connection

Question

This only started happening recently, when I torrent something it crashes the router after a while. I noticed with uTorrent it happens almost immediatly and with qBittorrent only after like 10 minutes.
I have to reset the router to get it to work again.

IP flooding protection is off and I cant find anything in my router settings that would limit connections in any way. The weird thing is, it worked fine until like half a month ago, and I didnt really change anything.

Thanks in advance!

Answer 1

Reduce the number of simultaneous connections in your bittorrent client. What is likely happening is that in the router the open connection list table is getting full and once full can no longer accept new connections until some of the existing ones time out.

See: Here.

Answer 2

Routers contain stateful NATs and firewalls. Which means they keep state for each "connection".

Sadly, connection here often also means that every single, normally stateless UDP request-reply exchange is tracked as a separate connection, despite RFC 4787 prescribing endpoint-independent mappings (EIM), i.e. just one mapping per port.

The DHT feature implemented in most bittorrent clients does many such exchanges to many different IPs which can lead to overflows of the connection tracking tables and subsequently to crashes/hangs/other temporary disruptions.

In theory enabling UPnP on the router or manually mapping the ports can help if that changes its behavior to use EIMs. But again, not all routers implement that.

IP flooding protection is off

It is unlikely to help unless you have IPv6, since NAT would still be enabled, but you could still try completely disabling its firewall.