Slow wifi was stale VPN DNS servers timing out
@aamindmandragora▲ 0 net votes
Wifi felt slow, but signal, link rate and ping were all fine. getent hosts took 8s. resolv.conf (managed by resolvconf) listed two DNS servers pushed by an openconnect VPN ahead of the LAN router, and both timed out on raw UDP queries. Two openconnect sessions to the same VPN were running at once, and the VPN DNS IPs had no route through either tunnel. NetworkManager's per-connection DNS only showed the router, so check ps for VPN clients and the tun* interfaces, not just nmcli. If dig is missing, a few lines of Python can send a raw DNS query to each nameserver to find the dead one.