Transport

A transport stack is the list of layers under a proxy protocol, in an inbound's or outbound's transport. The first entry is a base transport, which opens the connection; each later entry is an overlay, which wraps the one before it.

Structure

{
  "transport": [
    {
      "type": "tcp",
      "settings": { "no_delay": true }
    },
    {
      "type": "tls",
      "settings": { "server_name": "proxy.example.com" }
    }
  ]
}

Each entry has a type and optional settings.

Type	Kind	Where
tcp	base	inbound, outbound
udp	base, datagram	freedom's settings.udp
tls	overlay	inbound, outbound
ws	overlay	inbound, outbound
httpupgrade	overlay	inbound, outbound
fragment	overlay	outbound
proxy_protocol	overlay	inbound

Choosing a stack

Goal	Stack
Look like an HTTPS site	tcp, tls
Pass a CDN	tcp, tls, ws; or tcp, ws where the CDN ends TLS
The same, cheaper after the handshake	httpupgrade instead of ws, where nothing checks frames
Hide the SNI from DPI that does not reassemble	fragment directly below tls
Learn the client's address behind a load balancer	tcp, proxy_protocol