This is now deprecated.

1. Linux has changed something recently.
   Now it requires a 60s delay before creating a listen socket after punching a TCP hole.
2. My ISP no longer supports this - I'll be switching to a new one anyway.
3. TCP needs to die. Use UDP.
4. IPv4 needs to die. Use IPv6.
5. If desperate, use Vultr's $3.50 VPS or DigitalOcean's $4.00 VPS.