Skip Navigation
OpenBSD @lemmy.sdf.org z3bra @lemmy.sdf.org

USB tether (urndis(4)) not working

Hey everyone,

I decided after many year to try again to slap OpenBSD on my old Acer Aspire one. The Wifi adapter is not supported, but I was thinking about using my phone to get network connectivity out of it. Unfortunately I'm hitting a strange behavior: ifconfig urndis0 autoconf works as expected, and I get an IP over DHCP. Ping and DNS resolution work as expected, but when I try any TCP connection, the connectivity simply stops working, and I cannot even ping the gateway anymore. dmesg doesn't say anything about it.

Has anyone encountered this already ?

4
4 comments

  • Hm... You could try tcpdump(8), e.g. tcpdump -i urndis0; there might be some hints there as you do a ping, then DNS lookup, then try to establish a TCP connection.

    If it's just TCP, it would be interesting to see if routing all traffic through a WireGuard tunnel with wg(4) prevents the connection to the gateway from falling over. That's not really a solution but it could be an interesting test.

    Finally, from ifconfig(8), it looks like you can enable per-driver debug mode. I think ifconfig urndis0 debug will enable it.

    • I'll try the debug command for ifconfig eventually. I took the hardest path to fix this issue however as I scrapped a supported wireless card from another computer and installed it on the netbook. Now it has wifi natively hehe. Thanks for your help!

  • I saw some behavior like this in networks where I created an L2 adjacency between the gateway and two downstream dhcp-configured LAN devices, when the gateway was apparently configured to demand that there only be a single one.

    • In my case the setup is fairly straightforward though. There's my phone and the netbook. I suspect an issue with the driver, so I'll check it further.