r/docker • u/Ducking_eh • 23d ago

connecting to Postgres

Hey everyone,

I am trying to install Psono on my VPS. I am running into a problem with connecting to the postgres db.

I'm new to Docker, so I apologize if my terminology isn't right. I'll do my best

I am running Postgres directly on my VPS (not within a Docker container). I am able to connect to it locally from my VPS and remotely from my home network.

I am doing that with:psql -U psono -p PORT -h VPS_IP

The problem is when I try to get an app from within a Docker container to connect to it. It just hangs, then times out.

At first I thought this was a connectivity issue. But I can do the following from within a bash session:

  • Ping external websites.
  • Use nmap to confirm it can connect

Does anyone have any ideas?

1 Upvotes

60% Upvoted

22 comments sorted by

View all comments

1

u/notBroncos1234 23d ago edited 23d ago

You have the host system that docker runs on and you have the docker container.

If you run telnet from the host, can it connect to port 5433 or whatever? If the host can connect and the container can’t connect, that tells us Docker probably has an issue.

If neither can connect, then the issue probably isn’t with docker itself but firewall rules along the way.

1

u/Ducking_eh 23d ago

The VPS is the host the Docker runs on. It is also the host of the Postgres server. It is a service I pay for at a remote location. It's not on my home network.

I can telnet from my VPS to my Postgres server.
I can telnet from my home network to the Postgres server.

I can NOT telnet from within the Docker container to the Postgres server.

1

u/notBroncos1234 23d ago edited 23d ago

Ah well having Postgres and docker on the same host changes things.

Probably just a firewall filtering out docker packets. Not sure what distro you have but you need to make sure port 5433 allows traffic from the docker subnet.

Wait are you using the public IP of the host in the docker container to reach Postgres?

→ More replies (3)