E2E: SSH AcceptEnv with Containerized Server

This guide shows how to run a disposable SSH server container that accepts specific environment variables, then verify that WebSSH2 forwards them end‑to‑end.

1) Start a test SSH server (AcceptEnv)

Using billchurch/ssh_test (alpine):

docker run --rm -d \
  -p 2289:22 \
  -e SSH_USER=testuser \
  -e SSH_PASSWORD=testpassword \
  -e SSH_AUTHORIZED_KEYS="$(cat ./test-keys/*.pub 2>/dev/null || true)" \
  -e SSH_DEBUG_LEVEL=3 \
  -e SSH_PERMIT_PASSWORD_AUTH=yes \
  -e SSH_PERMIT_PUBKEY_AUTH=yes \
  -e SSH_CUSTOM_CONFIG=$'PermitUserEnvironment yes\nAcceptEnv FOO' \
  ghcr.io/billchurch/ssh_test:alpine

Notes:

• Port 2244 maps to container SSH port 22.
• Accepts FOO from the client via AcceptEnv.

2) Start WebSSH2

DEBUG=webssh2:* npm run start

3) Connect with env via URL

Open your browser to:

http://localhost:2222/ssh/host/localhost?port=2244&env=FOO:bar

Authenticate with testuser / testpassword.

You should see logs like:

routes: Parsed environment variables: { FOO: 'bar' }
ssh: shell: ... and env options: { env: { TERM: 'xterm-color', FOO: 'bar' } }

On the SSH server logs you will see req env and permission for FOO.

4) Verify in the terminal

In the WebSSH2 terminal, run:

printenv FOO

Expected output:

bar

Troubleshooting

• Ensure you used &env=... not a second ? in the URL.
• If you configured ssh.envAllowlist, include FOO in the allowlist.
• Check that the SSH server includes AcceptEnv FOO and PermitUserEnvironment yes.
• Review README “Troubleshooting: AcceptEnv on SSH server”.