( < point-to-point tunneling protocol,
"kakspunkttunnelduse protokoll")

olemus
kunagine (1999) protokollikavand,
mida IETF ei kinnitanud standardiks;
on nõrgema turbega kui IPSec, on leitud olulisi turvaauke
= an obsolete protocol for implementing virtual private networks

ülevaateid
https://en.wikipedia.org/wiki/Point-to-Point_Tunneling_Protocol

http://www.h-online.com/security/features/A-death-blow-for-PPTP-1716768.html

http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.503.7298&rep=rep1&type=pdf

https://datatracker.ietf.org/doc/html/rfc2637