How to connect to windows postgres Database from WSL - postgresql

Question

I'm running Postgres 11 service on my Windows computer.
How can I connect to this database from WSL?
When I try su - postgres:
postgres#LAPTOP-NQ52TKOG:~$ psql
psql: could not connect to server: No such file or directory
Is the server running locally and accepting
connections on Unix domain socket "/var/run/postgresql/.s.PGSQL.5432"
It's trying to connect to a Postgres in WSL. I don't want to run Ubuntu Postgres using:
sudo /etc/init.d/postgresql start

Answer 1

WSL2 assigns IP address to the Windows host dynamically and the IP addresses can change without even rebooting Windows (see Notes below). So to reliably connect we'll need to:
Allow Windows and Postgres to accept connections from the WSL2 IP address range (not allowed by default)
From WSL2, determine the Windows/Postgresql host's IP address (which is dynamic) when connecting via psql. We'll make this convenient via .bashrc and alias.
Unfortunately I couldn't find the exact specification for the WSL2 IP address range. From several tests/reboots it appears that WSL2 is assigning IP addresses primarily in range of 172.*.*.* but I have occasionally been assigned 192.*.*.* so we'll use these when configuring the firewall and Postgres.
Add Windows Firewall Inbound Port Rule for WSL2 IP Addresses:
Open Windows Defender Firewall with Advanced Security
Click New Rule...
Select Port for rule type
Select TCP and for Specific local ports enter 5432
Select Allow the connection. Connecting from WSL2 won't be secure so don't select the secure option
Select at least Public. Can select Domain and Private as well. I could only connect if Public was selected
Name the rule e.g. Postgres - connect from WSL2 and create it
Right click newly created rule and select Properties then click on the Scope tab
Under Remote IP address, select These IP addresses then click Add... and enter range 172.0.0.1 to 172.254.254.254
Repeat step 9 for IP address range 192.0.0.1 to 192.254.254.254
Click Apply then OK
Make sure rule is enabled
Configure Postgres to Accept Connections from WSL2 IP Addresses
Assuming a default install/setup of Postgresql for Windows the following files are located under C:\Program Files\PostgresSQL\$VERSION\data
Verify that postgresql.conf has following set:
listen_addresses = '*'
This should already be set to '*' so nothing do here.
Update pg_hba.conf to allow connections from WSL2 range e.g. for Postgresl 12:
# TYPE DATABASE USER ADDRESS METHOD
# IPv4 local connections:
host all all 127.0.0.1/32 md5
host all all 172.0.0.0/8 md5
host all all 192.0.0.0/8 md5
For Postgresql 13+ you should use scram-sha-256 as the method.
Restart Postgres for changes to take effect. This can be done either from the Windows Services app or from cmd with Administrator privileges e.g. for Postgresql 12:
net stop postgresql-x64-12
net start postgresql-x64-12
WSL Shell Conveniences
In WSL, add following to your ~/.bashrc or similar:
# Add DNS entry for Windows host
if ! $(cat /etc/hosts | grep -q 'winhost'); then
echo 'Adding DNS entry for Windows host in /etc/hosts'
echo '\n# Windows host - added via ~/.bashhrc' | sudo tee -a /etc/hosts
echo -e "$(grep nameserver /etc/resolv.conf | awk '{print $2, " winhost"}')" | sudo tee -a /etc/hosts
fi
Then reload your .bashrc changes: source ~/.bashrc
Usage
psql -h winhost -p 5432 -U postgres
Notes:
The IP address assigned to the Windows host by WSL2 is not the same as the IP address assigned to your physical Windows machine on your network. WSL2 uses vEthernet connections.
You can inspect the vEthernet connections via Control Panel\Network and Internet\Network Connections
Note that when looking at the IPv4 properties that the IP addresses will appear as if they are statically set but they aren't! Try rebooting and inspecting IPv4 properties again
If one day you're unable to connect to Postgres, check that winhost is in the IP address range per firewall rules. Could be WSL has assigned an IP address that we weren't expecting!

Answer 2

In WSL2 you need to use host IP to connect
to get host IP
grep nameserver /etc/resolv.conf | awk '{print $2}'
then you need to allow TCP 5432 inbound Rules in 'Windows Defender Firewall with Advanced Security'
I made my self PS.you still need to allow TCP 5432 in Firewall
put this in ~/.bashrc
cat /etc/hosts | grep 172.; test $? -eq 0 && $1 || echo -e "$(grep nameserver /etc/resolv.conf | awk '{print $2, " host"}')\n$(cat /etc/hosts)" | sudo tee /etc/hosts
its append host IP to /etc/hosts if not exist before(usually happened when restart wsl or computer)
then
psql -h host -p 5432 -U postgres

Answer 3

Specify your host, port, and username explicitly
For example:
psql -h 127.0.0.1 -p 5432 -U postgres

Answer 4

For me what worked was to follow these steps:
Change pg_hba.conf to listen on all interfaces: host all all 0.0.0.0/0 trust
Open firewall for postgresql
Use one of the hostnames in /etc/hosts that pointed to the ip of my host. This hostname for me was: host.docker.internal

Answer 5

This issue can be fixed in two possible ways
Specify the host and user name explicitly
psql -h localhost -U postgres
Or
Navigate to the runpsql.sh file and run the query
/Library/PostgreSQL/14/scripts/runpsql.sh
Now run the psql query by entering password (if needed)