Documentation / Reserved Names

Reserved Names

Certain tunnel IDs are reserved and cannot be used with the -id flag

Why are names reserved?

To prevent confusion, protect infrastructure, and avoid abuse, stunl reserves a set of subdomain names that cannot be used as tunnel IDs. If you try to use one, your tunnel will fail to connect.

This will not work 
$ stunl -port 3000 -id test
  Error: Subdomain 'test' is reserved by the system and cannot be used.

Instead, use a unique name like my-test, testing, or myapp-dev.

System Infrastructure

Reserved for core services and common infrastructure patterns.

admin api app assets auth cdn console dashboard dns files ftp grafana grpc health images img media metrics monitoring ns ns1 ns2 portal prometheus sftp ssh static status vpn websocket ws wss www

Authentication & Email

Names commonly associated with login flows and email services.

login logout oauth register signin signup sso email imap mail pop smtp

Development & Testing

Common development environment names. Use more specific names like my-test or project-staging instead.

demo dev preview qa sandbox staging test

Security & Administrative

Sensitive names that could be used for phishing or impersonation.

administrator billing help payment payments root superuser support

Brand Protection

Reserved to prevent impersonation of stunl services.

localshare pentest simple-tunnel simpletunnel tunnel tunnels

Abuse Prevention

Names that could cause confusion with local or internal network addresses.

internal intranet local localhost private

Tips

Use prefixes

Add your project or username as a prefix: myapp-api, val-staging, acme-demo

Reserve your names

Pro users can reserve custom tunnel IDs in the portal so they're always available.

Skip the -id flag

If you don't need a specific name, omit -id entirely and stunl will generate a random one for you.

Next Steps