We wish you well on your journey into the world of NAT! Hopefully, this chapter will prove useful when you are stuck or prepare you in advance for a battle with an ALG .That would really be awful! If you memorize everything in this chapter and somehow still have problems, you can always come online and ask other FreeSWITCH community members for help. One final word of wisdom that can make you look smart is that if next time you notice someone complaining that their calls fail 30 seconds after they start, then yes, it's a NAT problem. This has been shown in the following diagram:

In some cases FreeSWITCH can't fix the problem and you will need to fix or replace the NAT device.