DEFAULTPORT

DEFAULTPORT is a term used in software development to designate the port number that a network service should use by default when no explicit port is provided. In many codebases, the value is defined as a constant named DEFAULTPORT, DEFAULT_PORT, or defaultPort and is read by the service at startup to determine which port to bind to.

The actual numeric value of DEFAULTPORT varies by project and is not standardized. Common choices include well-known ports such as 80 for HTTP and 443 for HTTPS, as well as non-privileged or development-friendly defaults such as 8080 or 8000. Some applications may keep 80 or 443 for production services, while others default to higher, non-privileged ports to simplify testing and deployment.

Usage and override: If a user does not specify a port, the service will attempt to bind to DEFAULTPORT. This default can typically be overridden through configuration files, environment variables, or command-line options, allowing operators to customize the listening port without changing the code.

In libraries and frameworks, a module may expose DEFAULTPORT as part of its API to inform consumers of the default listening port. Developers may rely on this constant to provide sensible defaults or to document expected behavior.

Security considerations: Relying on default ports can expose services to common scans and attacks. Administrators are advised to change default ports in production, implement appropriate firewall rules, and follow best practices for service hardening.

See also: default port, list of well-known ports, port forwarding.