PPTP uses IP protocol 47 (GRE) and TCP port 1723
IPSec uses IP protocol 50 (ESP) and UDP ports 500 & 4500
If this is a SOHO router you may not see the opition to allow the IP
protocols through the router, rather you may only get an option to allow VPN
passthrough.
**NOTE** ports and protocols are different i.e. TCP is protocol 6, UDP is
protocol 17 the protocols then use ports to communicate on.
