The listen_addresses GUC determines which TCP interfaces PostgreSQL binds to, but it does not enforce authentication or authorization. Relying solely on this setting creates a false sense of security regarding network exposure. Access control must be handled separately through pg_hba.conf or external firewall rules.
- listen_addresses only binds sockets; it does not filter connections.
- Never use this GUC as a security boundary for network access.
- Configure pg_hba.conf to enforce authentication and authorization.
- Use OS-level firewalls to restrict traffic before it reaches PostgreSQL.