Yes, I tried it. :] it had no effect.
So, update. The problem has now been worked around.
I changed two things:
- Killed IPv6 in sysctl.conf
- Added the school's DNS server in "Network" settings
[1] was not enough by itself to solve my problem, firefox still could not find servers, though wget could.
[2] I suspect this is what helped here.
Yes, I mean "Network" settings, not "Network Connections" settings.
I had never used "Network" settings before.
It was weirdly set too:
- DNS Server had just one entry:
127.0.1.1, and not the school's DNS that are correctly set in "Network Connections" settings - Search Domains had my school's domain, which it took from "Network Connections" settings
I don't understand why one settings was mirrored there but not the other.
Next time I power-cycle, I will re-enable IPv6 and see if it breaks things again.
But no one else on the network is having host resolution issues, I'm the only one affected and we're all in the same LAN.
Maybe this is what the "Network" settings is using?