headscale/docs/TLS.md

Running the service via TLS (optional)

tls_letsencrypt_hostname: ''
tls_letsencrypt_listen: ":http"
tls_letsencrypt_cache_dir: ".cache"
tls_letsencrypt_challenge_type: HTTP-01

To get a certificate automatically via Let's Encrypt, set tls_letsencrypt_hostname to the desired certificate hostname. This name must resolve to the IP address(es) Headscale is reachable on (i.e., it must correspond to the server_url configuration parameter). The certificate and Let's Encrypt account credentials will be stored in the directory configured in tls_letsencrypt_cache_dir. If the path is relative, it will be interpreted as relative to the directory the configuration file was read from. The certificate will automatically be renewed as needed.

tls_cert_path: ''
tls_key_path: ''

Headscale can also be configured to expose its web service via TLS. To configure the certificate and key file manually, set the tls_cert_path and tls_cert_path configuration parameters. If the path is relative, it will be interpreted as relative to the directory the configuration file was read from.

Challenge type HTTP-01

The default challenge type HTTP-01 requires that Headscale is reachable on port 80 for the Let's Encrypt automated validation, in addition to whatever port is configured in listen_addr. By default, Headscale listens on port 80 on all local IPs for Let's Encrypt automated validation.

If you need to change the ip and/or port used by Headscale for the Let's Encrypt validation process, set tls_letsencrypt_listen to the appropriate value. This can be handy if you are running Headscale as a non-root user (or can't run setcap). Keep in mind, however, that Let's Encrypt will only connect to port 80 for the validation callback, so if you change tls_letsencrypt_listen you will also need to configure something else (e.g. a firewall rule) to forward the traffic from port 80 to the ip:port combination specified in tls_letsencrypt_listen.

Challenge type TLS-ALPN-01

Alternatively, tls_letsencrypt_challenge_type can be set to TLS-ALPN-01. In this configuration, Headscale listens on the ip:port combination defined in listen_addr. Let's Encrypt will only connect to port 443 for the validation callback, so if listen_addr is not set to port 443, something else (e.g. a firewall rule) will be required to forward the traffic from port 443 to the ip:port combination specified in listen_addr.