Ufw (Uncomplicated Firewall) is program for managing a netfilter
firewall.  It provides a command line interface and aims to be
uncomplicated and easy to use.

Add the following code to /etc/rc.d/rc.local to start Ufw at boot time:

if [ -x /lib/ufw/ufw-init ]; then
  /lib/ufw/ufw-init start
fi

Ufw comes with a number of common application profiles.  Create
additional application profiles under /etc/ufw/applications.d.
Each profile should contain a list of rules which include a title,
description, and port(s) or port range.

A custom application profile should look similar to this:

[Application]
title=Application title
description=A description for the application.
ports=137,138/udp|139,445/tcp

Where xx.xx.xx.xx is the IP address of an external host, enable this
application profile by executing the following as root:

# ufw allow from xx.xx.xx.xx app Application