PostgreSQL default port is 5432, registered with IANA. Multiple installations on one host use 5432, 5433, 5434 etc. (each major version gets the next port). Change the port via port = XXXX in postgresql.conf, then sudo systemctl reload postgresql. The team that uses non-standard ports for security-through-obscurity knows the real protection is the firewall, not the port.
Table of contents
- The default port
- Why 5433, 5434, etc.
- Change the port
- Connection strings
- Firewall considerations
- When to use non-standard port
- FAQ
The default port
PostgreSQL’s IANA-registered port is 5432. Confirmed in the Postgres docs.
psql -h localhost -p 5432 -U postgresIf unspecified, psql uses 5432.
Why 5433, 5434, etc.
PostgreSQL Apt repo’s postgresql-XX packages auto-assign ports:
- 16: 5432
- 17: 5433
- 18: 5434
- etc.
Run multiple major versions side by side:
sudo apt install postgresql-16 postgresql-17 postgresql-18
# All running, on different portsThe team that runs multiple versions has no port conflicts.
Change the port
Edit postgresql.conf:
port = 5433Then sudo systemctl reload postgresql.
Verify:
ss -tlnp | grep 5433The team that has the config has the new port listening.
Connection strings
With port change:
postgresql://user:pass@host:5433/dbnameOr keyword/value:
host=db.example.com port=5433 user=postgres dbname=mydbThe team that updates connection strings has clients connecting to the new port.
Firewall considerations
Open the new port:
sudo ufw allow 5433/tcpThe team that has a firewall allows the right port. The team that forgets has no remote connections.
When to use non-standard port
- Multi-version on one host (5432, 5433, 5434).
- Dev/staging that needs separation from prod.
- Security-through-obscurity (minor benefit).
The team that uses non-standard ports for security knows it’s a minor defense-in-depth, not a primary control.
FAQ
What’s the default port for PostgreSQL?
5432, registered with IANA.
Can I run multiple versions on different ports?
Yes - PGDG’s packages auto-assign 5432, 5433, 5434 for v16, 17, 18. The team that runs multiple versions for testing has them coexisting.
How do I find which port Postgres is on?
ss -tlnp | grep postgres or cat /etc/postgresql/<version>/main/postgresql.conf | grep ^port. The team that uses these finds the listening port.
Is it safe to run Postgres on a non-standard port?
Slightly safer (reduces drive-by scans) but the real protection is firewall + auth + TLS. The team that uses port 5432 with proper security is fine.
What if I change the port but forget to update connection strings?
Clients fail to connect with ‘connection refused’ or timeout. Fix: update connection strings and firewall rules together.
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