Arch Linux

Soukyuu

Member

Registered: 2014-04-08

Posts: 854

Tweaking network parameters for P2P purposes?

I suppose arch is tweaked towards normal network use, not P2P.  I'm using my home server to seed various torrents 24/7 and now and then my connection gets saturated by some traffic, which my router counts as realtime priority. This results in essentially dead net for every other client on the network. I'm also seeing stuff like

TCP: request_sock_TCP: Possible SYN flooding on port <my_p2p_port>. Sending cookies.  Check SNMP counters.

in my dmesg.

Searching around, it looks like I could potentially solve it by increasing the "net.ipv4.tcp_max_syn_backlog" sysctl variable. Currently, it's set to 128, but max connection allowed in my torrent client are 200. Could it be that this is what is causing the "flood prevention" to kick in?
Or am I reading this wrong, and I should be decreasing that value to prevent the packet spam? It's definitely the torrent client that is causing this, but it's not a torrent client specific issue, as I'm getting this with all torrent clients I tried (µtorrent, qBittorrent, kTorrent)

Any suggestions on other options I can tweak to improve P2P traffic without clogging other users? The torrent client is configured to use only 80% of up/downstream already.

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[ Arch x86_64 | linux | Framework 13 | AMD Ryzen™ 5 7640U | 32GB RAM | KDE Plasma Wayland ]