How do I kill the process using port 5432?

On macOS & Linux, run: "sudo systemctl stop postgresql || sudo kill -9 $(sudo lsof -t -i:5432)". On Windows PowerShell (as Admin), run: "Stop-Service postgresql* -Force".

Why am I getting "port 5432 already in use" (EADDRINUSE)?

This occurs when another background instance of postgres, pg_ctl or a zombie process is already bound to port 5432. Use the kill commands above to free the port immediately.

Database

Risk: High

Port 5432 — PostgreSQL Database

Q: Is Port 5432 safe to expose to the public internet?

Risk level is High. Never bind PostgreSQL to 0.0.0.0 without strict pg_hba.conf IP whitelisting and SSL connection enforcement (ssl=on). Restrict access to localhost or your VPC subnet.

Port 5432 is the official IANA assigned port for the PostgreSQL relational database management system. PostgreSQL servers listen on this port for incoming SQL client connections.

PORT NUMBER

5432

PROTOCOL

TCP

DEFAULT PROCESS

postgres, pg_ctl

FIREWALL TARGET

5432/tcp

Instant Terminal Fixes for Port 5432

macOS & Linux Terminal

1. Check who is listening on port 5432:

sudo ss -tulpn | grep 5432 || pg_isready -p 5432

2. Kill process occupying port 5432 (EADDRINUSE fix):

sudo systemctl stop postgresql || sudo kill -9 $(sudo lsof -t -i:5432)

3. UFW Firewall Allow rule:

sudo ufw allow from 10.0.0.0/16 to any port 5432 proto tcp

Windows PowerShell (Admin)

1. Check listening port:

Get-NetTCPConnection -LocalPort 5432

2. Force kill process on port 5432:

Stop-Service postgresql* -Force

3. Docker Port Forwarding Mapping:

docker run -p 5432:5432 -e POSTGRES_PASSWORD=securepass -d postgres:16

Common Error Encountered

could not connect to server: Connection refused. Is the server running on host "localhost" and accepting TCP/IP connections on port 5432?

Security Advisory & Hardening

Never bind PostgreSQL to 0.0.0.0 without strict pg_hba.conf IP whitelisting and SSL connection enforcement (ssl=on). Restrict access to localhost or your VPC subnet.

Frequently Asked Questions

Port 5432 Questions & Answers

Common questions regarding default services, kill commands, and firewall configurations.

Port 5432 is commonly used for PostgreSQL Database. Port 5432 is the official IANA assigned port for the PostgreSQL relational database management system. PostgreSQL servers listen on this port for incoming SQL client connections.

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