listenaddresses

Listen_addresses is a PostgreSQL server configuration parameter that controls which network interfaces the server binds to for TCP/IP client connections. It does not affect local Unix-domain socket connections, which use a separate mechanism.

The value is a comma-separated list of host names or IP addresses. Common options include localhost (loopback only), a specific IPv4 or IPv6 address such as 127.0.0.1 or ::1, or * to listen on all available interfaces. You can also combine addresses, for example localhost,192.168.1.100. The exact syntax is specified in postgresql.conf and can also be adjusted with a system-wide setting via ALTER SYSTEM.

Default behavior varies by installation, but many defaults restrict listening to the local machine for security. Enabling remote connections requires careful consideration of network security and access controls.

Changes to listen_addresses take effect when the server configuration is reloaded (not necessarily restarted). A configuration reload can be performed with a signal such as pg_ctl reload or a suitable administration command, after which the server binds to the new addresses without a full restart.

Security considerations are important: exposing listen_addresses to widely reachable networks increases the potential attack surface. When remote access is needed, restrict the addresses to trusted networks, and pair listen_addresses with appropriate authentication rules in pg_hba.conf and a firewall.

In practice, the parameter works in concert with port settings and host-based authentication to define who can connect to which databases.