SysAdmin Blog

so I didn't notice that my OpenBSD vserver had broken IPv6 for quite some time...

Alexander Bochmann Sunday 19 of February, 2017
...until I had a look at the DNS server log, which showed errors contacting other servers via IPv6.

The hoster I'm using has a somewhat strange IPv6 setup where you get a /64 for your system, but the default gateway is just fe80::1 - when I originally set up the system, I put that into /etc/mygate whithout thinking much about it.

This initially was ok for quite some time, but it seems the default route vanished at some point. (In retrospect I don't quite understand why the setup ever worked at all, as the lo0 lookback interface has fe80::1 auto-assigned too...)

Then I remembered that fe80:: carries interface tags, since it exists on any IPv6-enabled interface, and the OS needs some way to decide which fe80:: it has to deal with right now.

Edited /etc/mygate accordingly, and things are back to normal (vio is OpenBSD's VirtIO network device driver, so my virtual ethernet device is vio0):