`server_url` is the external URL via which Headscale is reachable. `listen_addr` is the IP address and port the Headscale program should listen on. `ip_prefix` is the IP prefix (range) in which IP addresses for nodes will be allocated (default 100.64.0.0/10, e.g., 192.168.4.0/24, 10.0.0.0/8)
```yaml
log_level: debug
```
`log_level` can be used to set the Log level for Headscale, it defaults to `debug`, and the available levels are: `trace`, `debug`, `info`, `warn` and `error`.
```yaml
private_key_path: private.key
```
`private_key_path` is the path to the Wireguard private key. If the path is relative, it will be interpreted as relative to the directory the configuration file was read from.
```yaml
derp_map_path: derp.yaml
```
`derp_map_path` is the path to the [DERP](https://pkg.go.dev/tailscale.com/derp) map file. If the path is relative, it will be interpreted as relative to the directory the configuration file was read from.
```yaml
ephemeral_node_inactivity_timeout": "30m"
```
`ephemeral_node_inactivity_timeout` is the timeout after which inactive ephemeral node records will be deleted from the database. The default is 30 minutes. This value must be higher than 65 seconds (the keepalive timeout for the HTTP long poll is 60 seconds, plus a few seconds to avoid race conditions).
