How to fix Error response from daemon: driver failed programming external connectivity: iptables failed in Docker

# Restart Docker service
sudo systemctl restart docker

# Verify Docker is running
sudo systemctl status docker

sudo service docker restart

# Check for DOCKER chain in NAT table
sudo iptables -L -n -t nat | grep -i docker

# List all chains to see if DOCKER exists
sudo iptables -S | grep DOCKER

# Create DOCKER chain (if missing)
sudo iptables -N DOCKER
sudo iptables -t nat -N DOCKER

# Check if firewalld is active
sudo systemctl status firewalld

# If using firewalld, restart it then Docker
sudo systemctl restart firewalld
sudo systemctl restart docker

# Reload firewalld without losing Docker rules (preferred)
sudo firewall-cmd --reload
sudo systemctl restart docker

sudo systemctl start iptables
sudo systemctl restart docker

# Check iptables version and variant
iptables --version
# If it shows (nf_tables), you're using nftables backend

# On Debian/Ubuntu
sudo update-alternatives --set iptables /usr/sbin/iptables-legacy
sudo update-alternatives --set ip6tables /usr/sbin/ip6tables-legacy

# Restart Docker
sudo systemctl restart docker

# View available alternatives
sudo update-alternatives --config iptables
# Select the legacy option (usually option 1)

# Load required modules
sudo modprobe ip_tables
sudo modprobe iptable_nat
sudo modprobe iptable_filter
sudo modprobe iptable_raw

# For IPv6 support
sudo modprobe ip6_tables
sudo modprobe ip6table_nat

# Create module configuration file
sudo bash -c 'cat > /etc/modules-load.d/docker-iptables.conf << EOF
ip_tables
iptable_nat
iptable_filter
iptable_raw
EOF'

sudo systemctl restart docker

# Check daemon configuration
cat /etc/docker/daemon.json

{
  "iptables": true
}

# Check Docker service configuration
sudo systemctl show docker | grep -i "ExecStart"

# Or check process
ps aux | grep dockerd

# Stop Docker
sudo systemctl stop docker

# Remove Docker network configuration
sudo rm -rf /var/lib/docker/network

# Remove Docker bridge interface
sudo ip link delete docker0

# Start Docker
sudo systemctl start docker

# Run container with host networking (no port mapping needed)
docker run --network host nginx

# For docker-compose, add network_mode:
# services:
#   web:
#     image: nginx
#     network_mode: "host"