Flags

The NATS server has many flags to customize its behavior without having to write a configuration file.

The configuration flags revolve around:

Server Options

Flag	Description
`-a`, `--addr`	Host address to bind to (default: `0.0.0.0` - all interfaces).
`-p`, `--port`	NATS client port (default: 4222).
`-P`, `--pid`	File to store the process ID (PID).
`-m`, `--http_port`	HTTP port for monitoring dashboard (exclusive of `--https_port`).
`-ms`, `--https_port`	HTTPS port monitoring for monitoring dashboard (exclusive of `--http_port`).
`-c`, `--config`	Path to NATS server configuration file.
`-sl`, `--signal`	Send a signal to nats-server process. See process signaling.
`--client_advertise`	Client HostPort to advertise to other servers.
`-t`	Test configuration and exit

Flag	Description
`-js`, `--jetstream`	Enable JetStream functionality.
`-sd`, `--store_dir`	Set the storage directory.

The following options control straightforward authentication:

Flag	Description
`--user`	Required username for connections (exclusive of `--token`).
`--pass`	Required password for connections (exclusive of `--token`).
`--auth`	Required authorization token for connections (exclusive of `--user` and `--password`).

The following flags are available on the server to configure logging:

Flag	Description
`-l`, `--log`	File to redirect log output
`-T`, `--logtime`	Specify `-T=false` to disable timestamping log entries
`-s`, `--syslog`	Log to syslog or windows event log
`-r`, `--remote_syslog`	The syslog server address, like `udp://localhost:514`
`-D`, `--debug`	Enable debugging output
`-V`, `--trace`	Enable protocol trace log messages
`-VV`	Verbose trace (traces system account as well)
`-DV`	Enable both debug and protocol trace messages
`-DVV`	Debug and verbose trace (traces system account as well)
`--max_traced_msg_len`	Maximum printable length for traced messages. 0 for unlimited

Flag	Description
`--tls`	Enable TLS, do not verify clients
`--tlscert`	Server certificate file
`--tlskey`	Private key for server certificate
`--tlsverify`	Enable client TLS certificate verification
`--tlscacert`	Client certificate CA for verification

You can read more about tls configuration here.

The following flags are available on the server to configure clustering:

Flag	Description
`--routes`	Comma-separated list of cluster URLs to solicit and connect
`--cluster`	Cluster URL for clustering requests
`--no_advertise`	Do not advertise known cluster information to clients
`--cluster_advertise`	Cluster URL to advertise to other servers
`--connect_retries`	For implicit routes, number of connect retries