When I connected my laptop running Arch Linux to a new WiFi this morning, it worked for a brief moment then all connections were dropped. Connecting to the same WiFi with phone or Macbook works fine so the problem is at Arch LInux(AL)’s end.

Then I noticed if I do a route it actually showed 2 entries for the LAN. I took a closer look and saw there were 2 IPs for the wireless interface!

Strange enough if I connect to the hotspot of my phone, AL will also have 2 IPs but the connection is still working.

So I googled a bit why there will be 2 IPs, here’s what I got:

https://raspberrypi.stackexchange.com/questions/13359/where-does-my-secondary-ip-come-from

Finally, after I shutdown and disabled the dhcpcd service with

sudo systemctl disable dhcpcd
sudo systemctl stop dhcpcd

and restarted NetworkManager, the problem is fixed. Guess some WiFi AP is more tolerant than others.

🙂