Yes, this behavior is typical for PostgreSQL when listen_addresses is set to '*'. When PostgreSQL is configured to listen on all available network interfaces (via listen_addresses = '*'), it dynamically detects new interfaces and IP addresses without requiring a restart or service reload. So, as long as listen_addresses is '*' and the necessary network interfaces are configured correctly in the OS, PostgreSQL should continue functioning as expected without requiring a restart.
Why it is safe (under normal conditions) : -
OS handles the interfaces: PostgreSQL trusts the OS to expose valid network interfaces. If the OS assigns a new IP, PostgreSQL bound to '*' can accept connections immediately — no corruption or instability risks.
No restart required:As you observed, PostgreSQL doesn't need to rebind or restart because it's already listening on the wildcard interface (0.0.0.0 or :: for IPv6).
Used in production setups: Many production systems with HA setups (e.g., floating IPs or VIPs) rely on this behavior during failover
We've scheduled for an IP change for one of our dedicated PostgreSQL servers, running on version 13.8.
Our local tests, with listen_addresses = '*', show that the postgres listener accepts connections immediately to the new IP.
The same behavior is observed when adding a new network interface. Postgres accepts connections to the new network interface (and IP) immediately without requiring a restart.
Is it safe to assume this is the default behaviour ? How does the instance detect new interfaces and their IP(s) and begin listening on them without needing a service reload or restart?
