When working with WSL2, it creates a virtualized network interface with its own IP range. The Windows host appears as a separate IP within this subnet (typically 172.x.x.1). This differs from WSL1's direct localhost bridging approach.


To properly connect from WSL2 to PostgreSQL on Windows:


PostgreSQL Configuration:
# In postgresql.conf
listen_addresses = '*'


Windows Firewall Rules:
netsh advfirewall firewall add rule name="PostgreSQL WSL2 Access" dir=in action=allow protocol=TCP localport=5432 remoteip=172.31.210.120


pg_hba.conf Update:
# Add this line with your WSL2 IP
host    all             all             172.31.210.120/20         scram-sha-256



Use these diagnostic commands:
# From WSL2 terminal:
ping 172.31.208.1
nc -zv 172.31.208.1 5432

On Windows, verify PostgreSQL is listening:
netstat -ano | findstr 5432

Basic connection string:
psql -h 172.31.208.1 -U postgres -d your_database

For applications using connection strings:
# Python example
import psycopg2
conn = psycopg2.connect(
    host="172.31.208.1",
    database="mydb",
    user="postgres",
    password="yourpassword"
)

You can use the Windows machine name if DNS resolution works:
# First try pinging the hostname from WSL2
ping YourWindowsHostname

# Then use in connection:
psql -h YourWindowsHostname -U postgres

For production workloads, consider:

Adding the connection to /etc/hosts in WSL2
Setting up SSH tunneling for secure connections
Using Unix domain sockets if running PostgreSQL in WSL2



When working with WSL2, it's crucial to understand its networking behaves differently from WSL1. WSL2 runs on a lightweight virtual machine with its own virtualized network interface. The Windows host appears as a separate IP address within this virtual network.
# To identify your Windows host IP from WSL2:
cat /etc/resolv.conf | grep nameserver | awk '{print $2}'

For PostgreSQL to accept remote connections, three key configuration files need attention:
# postgresql.conf (typically in C:\Program Files\PostgreSQL\13\data)
listen_addresses = '*'  # Allows listening on all interfaces
port = 5432            # Default PostgreSQL port

# pg_hba.conf (same directory)
# Add this line for WSL2 access:
host    all             all             172.31.210.120/20       scram-sha-256

The most common culprit for connection timeouts is Windows Firewall blocking the port. Here's how to add an inbound rule:
# PowerShell command to allow PostgreSQL port:
New-NetFirewallRule -DisplayName "PostgreSQL WSL2 Access" -Direction Inbound -LocalPort 5432 -Protocol TCP -Action Allow

Before attempting to connect with psql, verify basic connectivity:
# From WSL2 terminal:
nc -zv 172.31.208.1 5432  # Checks if port is open
ping 172.31.208.1         # Basic network connectivity

Try these different connection approaches from WSL2:
# Basic connection:
psql -h 172.31.208.1 -p 5432 -U postgres

# With password prompt:
PGPASSWORD=yourpassword psql -h 172.31.208.1 -U postgres

# Specifying database:
psql "host=172.31.208.1 port=5432 dbname=postgres user=postgres"

If direct connection proves problematic, set up port forwarding:
# Windows PowerShell command:
netsh interface portproxy add v4tov4 listenport=5432 listenaddress=0.0.0.0 connectport=5432 connectaddress=172.31.208.1

Enable detailed PostgreSQL logging to troubleshoot connection attempts:
# In postgresql.conf:
log_connections = on
log_disconnections = on
log_hostname = on
log_line_prefix = '%m [%p] %q%u@%d '
log_statement = 'all'

Instead of using IP addresses, configure WSL2 to resolve the Windows hostname:
# In WSL2's /etc/hosts:
172.31.208.1   windows-host

Now you can connect using:
psql -h windows-host -U postgres