Bash function to add or update a firewalld policy for accepting incoming traffic on a specified port.

add_or_update_firewalld_policy.sh

#!/bin/bash

# Function to add or update firewalld policy
add_or_update_firewalld_policy() {
  local protocol=$1
  local port=$2
  local zone=$3

  # Check if the rule already exists
  if firewall-cmd --zone=$zone --query-port=$port/$protocol; then
    echo "Rule already exists for $port/$protocol in zone $zone."
    return 0
  fi

  # Add the rule
  if firewall-cmd --zone=$zone --add-port=$port/$protocol --permanent; then
    echo "Successfully added $port/$protocol to zone $zone."
    
    # Reload the firewall
    firewall-cmd --reload
  else
    echo "Failed to add $port/$protocol to zone $zone."
    exit 1
  fi
}

# Test the function
for zone in home work internal public; do
  add_or_update_firewalld_policy "udp" "60001" $zone
done