Courtesy of Windows Tips and Tricks Update from Windows IT Pro,
PPTP
- PPTP tunnel maintenance traffic needs TCP 1723.
- PPTP tunneled data needs Protocol ID 47.
L2TP over IPSec
- Internet Key Exchange (IKE) needs UDP 500.
- IPsec Network Address Translation (NAT-T) needs UDP 5500.
- L2TP traffic needs UDP 1701.
Follow this link to get the program update that Microsoft released a few days go to its Anti-Spyware program. It extends the expiration date to the end of the year and also provides some fixes and enhancements. See the referenced page for more details.