I'm running Ubuntu 16.04.3 LTS as a server&router and recently I've set up a VPN connection (with private internet access) for a specific user (user: pia). I've configured the server to use PIA's DNS servers but ever since setting it up I've noticed significantly reduced internet speed for regular users, e.g. when running speedtest
Interestingly enough running speedtest as pia (sudo -u pia speedtest-cli) gives acceptable results given that it is going through a VPN, and is significantly faster than for other users. Also internet speeds from other clients behind the router aren't affected.
I get the feeling that for some reason the speedtest traffic by regular users is routed through the US, back to a server in my hometown Amsterdam, as it shows a latency of 260ms with a server distance of some 3km. Also when I ping google.com as a regular user i get:
64 bytes from yul02s05-in-f14.1e100.net (18.104.22.168): icmp_seq=1 ttl=53time=116 ms
while as user pia I get:
64 bytes from dh-in-f113.1e100.net (22.214.171.124): icmp_seq=1 ttl=48 time=32.2 ms
However if I ping 126.96.36.199 as a regular user I get latencies around 22ms, so at least dns lookup is inefficient.
Any clues are very welcome.