L2TP PPP/NCP Interop

Ze as an LNS against a real xl2tpd/pppd LAC, with FRR proving that a subscriber route makes it all the way into BGP.

Daemon

A peer-isolated Docker lab runs Ze as an LNS, a real xl2tpd/pppd LAC, and FRR as a BGP peer in separate privileged containers on an isolated bridge network. It proves the complete path from L2TP control tunnel through PPP LCP/IPCP, kernel pppN interface creation, dataplane connectivity, and BGP route redistribution from a live PPP session.

Two scenarios: full PPP/IPv4 dataplane proof with cleanup verification, and a subscriber /32 BGP redistribution scenario -- advertised to FRR when the session comes up, withdrawn on teardown.

Proves Full L2TP control tunnel, PPP LCP/IPCP negotiation, kernel pppN creation, BGP redistribution

Peer Real xl2tpd/pppd (LAC), optionally FRR as BGP peer

Requires Docker and a host kernel with PPPoL2TP support (Docker Desktop on macOS typically lacks this -- use the QEMU path instead)

Source docs/architecture/testing/l2tp-interop.md

l2tp-interop

# Docker lab, all scenarios
$ make ze-deployment-l2tp-ppp-docker-test

# single scenario, verbose
$ python3 test/l2tp-interop/run.py 01-ppp-ipv4

# QEMU path instead of Docker (needs tmp/kernel/vmlinuz)
$ make ze-qemu-l2tp-ppp-test

Prerequisites

Docker for the primary path. The QEMU path needs a staged kernel (make ze-kernel GOKRAZY_ARCH=arm64) and works where Docker Desktop's VM lacks the PPPoL2TP kernel module.

test/l2tp-interop/ lab source