How to Get a Docker Container's IP Address from the Host

When you're working with Docker, there are times when you need to access a container directly from your host machine. For example, you might want to debug a database, test an internal service, or allow traffic from the host into a container.

This tutorial shows you how to get a Docker container's internal IP address from the host and when it's appropriate to use it. We'll also cover common use cases, networking tips, and safer alternatives when possible.

Prerequisites

To follow along, make sure you have:

• Docker installed (Docker Engine 24 or later recommended)
• A running Docker container
• Terminal access to your host machine

Why You Might Need a Docker Container's IP Address

Docker assigns a private IP address to each container. This is usually in the 172.17.0.0/16 range for default bridge networks. Knowing a container's IP can be useful if:

• You want to test connectivity or API responses from the host
• You're debugging services like PostgreSQL, Redis, or custom apps
• You're configuring a firewall or network policy on the host

Keep in mind: container IPs can change if the container restarts or is recreated.

Step 1: Find the Running Container

Start by listing your running containers using:

docker ps

This gives you the container ID and name. For example:

CONTAINER ID   IMAGE         COMMAND                  NAMES
35c5a6f4a0d1   postgres:16   "docker-entrypoint.sh"   dev-db

Step 2: Inspect the Container's IP Address

Use docker inspect with the --format flag to pull just the IP address:

docker inspect -f '{{range .NetworkSettings.Networks}}{{.IPAddress}}{{end}}' dev-db

This returns something like:

172.17.0.3

This is the internal IP assigned to the container on the bridge network. You can use this address to connect from your host.

Step 3: Connect to the Container from the Host

Let's say your container is running a Postgres database. You can connect to it from your host like this:

psql -h 172.17.0.3 -U postgres

Or if it's running a web app:

curl http://172.17.0.3:8080

Important: this only works from the host machine. Other containers won't be able to connect this way unless they share a custom network.

Tip: Use docker exec Instead (For Debugging)

In many cases, it's easier to skip the IP and connect from inside the container directly:

docker exec -it dev-db psql -U postgres

This runs the command inside the container's environment.

Working with Custom Docker Networks

If you've created a custom user-defined bridge network, Docker gives you built-in DNS between containers.

# Create a custom Docker network
docker network create mynet

# Start a container on that network
docker run -d --name web --network mynet nginx

Now, any other container on mynet can access web using its container name:

curl http://web

This is more stable than relying on IPs, especially when containers are restarted or recreated.

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Getting a Docker container's IP address from the host is useful for quick debugging and testing, but it's not ideal for long-term setups. Instead, use Docker networks and container names for more reliable and scalable configurations.

If you find yourself needing container IPs regularly, it might be time to rethink your network strategy.