On 2021-12-15 06:09:12 +0000, Tim Woodall wrote: > On Tue, 14 Dec 2021, Dan Ritter wrote: > > > Vincent Lefevre wrote: > > > Hi, > > > > > > When I use USB tethering between my Debian/unstable laptop and my > > > Samsung Galaxy Note10+ phone (Android 11), everything is OK with > > > IPv6 connections (e.g. "wget -6"), but IPv4 connections freeze > > > (e.g. "wget -4" or "ssh -4"). I can notice this in particular when > > > testing with the same remote server. For instance, with "wget -4", > > > a few dozens of KB are downloaded, then the connection is completely > > > frozen. > > > > > > I don't have any issue with the mobile hotspot (thus wifi between the > > > laptop and the phone) or with a Cosmo under Android 9 (instead of the > > > Samsung Galaxy Note10+), but in both cases, this is much slower, and > > > I sometimes get wifi disconnections. > > > > > > On my Debian laptop, I'm using NetworkManager (nmcli). > > > > Have you investigated the MTU? This sounds like a mismatch > > between what your laptop and phone are using. > > > > Diagnosis (besides looking at connection details on both sides): > > ping with increasingly large packet sizes. If it works at small > > IPv4 packet sizes and then stops, that's the problem.
Indeed, this works up to ping -4 -s 1472 joooj.vinc17.net ping -6 -s 1452 joooj.vinc17.net > Yes, probably - --clamp-mss-to-ptmu in iptables might be what is needed. Thanks, but taking the rules from https://tldp.org/HOWTO/Adv-Routing-HOWTO/lartc.cookbook.mtu-mss.html I've tried iptables -A FORWARD -p tcp --tcp-flags SYN,RST SYN -j TCPMSS --clamp-mss-to-pmtu and iptables -A FORWARD -p tcp --tcp-flags SYN,RST SYN -j TCPMSS --set-mss 1024 and none of them have any effect. Or did I need something else? Any other suggestion? -- Vincent Lefèvre <vinc...@vinc17.net> - Web: <https://www.vinc17.net/> 100% accessible validated (X)HTML - Blog: <https://www.vinc17.net/blog/> Work: CR INRIA - computer arithmetic / AriC project (LIP, ENS-Lyon)
