How to Fix Docker Network Connectivity Issues

Docker network connectivity issues usually appear as containers being unable to reach the internet, other containers, or exposed services on a VPS.

Step 1: Verify Docker Is Running

Ensure Docker itself is active.

sudo systemctl status docker

If needed, restart Docker.

sudo systemctl restart docker

Step 2: Check Container Network Settings

Inspect the container’s network configuration.

docker inspect container_name

Look for IPAddress and Networks fields.

Step 3: Test Internet Connectivity from Inside the Container

Enter the container and test outbound access.

docker exec -it container_name sh
ping -c 3 google.com

If this fails, the issue is usually DNS or NAT-related.

Step 4: Fix Docker DNS Resolution

Docker sometimes inherits broken host DNS settings.

sudo nano /etc/docker/daemon.json

{
  "dns": ["8.8.8.8", "1.1.1.1"]
}

Restart Docker after changes.

sudo systemctl restart docker

Step 5: Check iptables and NAT Rules

Docker relies on iptables for networking.

sudo iptables -t nat -L -n

If NAT rules are missing, Docker networking will fail.

Step 6: Recreate the Docker Network

Corrupted networks can cause connectivity issues.

docker network ls
docker network rm network_name
docker network create network_name

Reconnect containers to the new network.

Step 7: Check Host Firewall Conflicts

Firewalls may block container traffic.

sudo ufw status
sudo ufw disable

If connectivity works after disabling, adjust firewall rules properly.

You may also want to review this related article: [Internal Link: related article title]

Optional Step: Reset Docker Networking Completely

As a last resort, reset Docker networking.

docker network prune
sudo systemctl restart docker