[pptp-server] FW: PPTP. PAP. and the compaq Microcom.

[David Luyer]

I've been thinking more about acting as a PAC and PNS.  While it is possible
there are issues which mean it's probably best as a compile time option to be
one or the other.

One issue is that I've just chopped some code which we might need to put back 
:-)  But I will re-write or resurrect it if we get to the point we need it, and
there's much more code needed for that bit to actually be useful.  That is the
multiple calls on one connection - not needed while we're acting as an IP
tunnelling PAC, but needed if we become a full-blown PNS.

Basically, we work as a PAC since IP tunnelling clients act as a PNS.  But if
we want to be able to do the PPTP back-end work for PACs we need to act as a 
PNS and to accept multiple calls from one PAC.

However, the Start Control Connection Reply will have to be different if we're
acting as a PAC or PNS (eg, max channels = 0 for PNS but = 1 for us as a PAC).

I currently see this as post-1.0 development but I guess it depends if people
are going to work on it now or not.  The actual amount of code needed isn't 
too severe, and should all be wrapped with something like #if PNS_MODE.

David.