PPTPD: options.pptpd options

[Gabriel Eduard Mititica]

Related Question:

I was able to set up the pptpd connection and fire it up - for using
a wireless card (wlan0) under VPN (ppp0)

My questions are:

- how can I be sure (how to test) that the connection of wlan0 goes
through ppp0 and it's secure?
- do I need to update the iptables accordingly? if yes, how? - would be
great if the answer is not ``man iptables''
- does it go always through tcp 1723 and gre 47?

Regards and thank you in advance,
Gabriel