Network

Access point

On an ASUS router, enable both IPv4 and IPv6 and set the IPv6 connection type to PPPoE / Native. Verify IPv6 connectivity at test-ipv6.com.

Connection quality

Trace the route to a host to see where latency is introduced:

# Linux / macOS
traceroute google.com

# Windows
tracert google.com

UPnP

# Find which process is handling UPnP
netstat -anp | grep 'miniupnpd'