How the agent connects

QUIC when the network allows it, WebSocket when it does not. No setup needed.

Automatic

The agent tries QUIC first (UDP, same port 443). If the network blocks UDP — hotels, offices with strict firewalls, some mobile providers — it uses WebSocket over TCP 443 and keeps working the same. If later the UDP path opens, it switches on its own, without cutting what it was serving.

When connecting, the agent says which of the two it used. With QUIC, losing a packet does not slow the rest of the requests and switching networks (WiFi to mobile) does not cut the session. If the server restarts, an agent installed as a service is back within seconds; one started by hand with lnkstart up can take up to 30 seconds more.

Force WebSocket

On your machine

LNKSTART_TRANSPORT=websocket lnkstart up

For networks where UDP works on and off, or to compare.

For QUIC to be available, the VPS needs UDP 443 open. If it is not, everything still works over WebSocket.

If a network doesn't get along with BBR

Over QUIC, the sending pace is set by BBR: with packet loss (bad wifi, mobile) it keeps its speed where the classic algorithm, Cubic, collapses. If a given network does worse with it, you can go back to Cubic: on the machine for what it sends (what visitors download) and on the server for what it sends (what they upload).

On your machine

LNKSTART_QUIC_CONGESTION=cubic lnkstart up

/etc/lnkstart/server.toml

[quic]
listen = "[::]:443"
congestion = "cubic"

On the VPS

sudo systemctl restart lnkstart-server

Behind an office proxy

Many offices do not go straight to the internet: everything goes through an HTTP proxy. The agent uses HTTPS_PROXY if it is set; for the installed service to use it too, save it:

On the agent's machine

lnkstart proxy http://proxy.company.local:3128
lnkstart proxy --ca-file company-ca.pem

With a user: http://user:password@proxy:3128. Through an HTTP proxy the agent uses the WebSocket (QUIC is UDP and does not cross it). If the network opens TLS with its own CA, --ca-file adds it to the ones the agent ships with; it never replaces them. lnkstart proxy alone says what it is using, and lnkstart proxy off removes it.