No need for ppp but of course you do need a network connection between the two boxes. i.e. send tcp packets back and forth on the chosen port.
To get the tap device in the kernel. I had
<M> Universal TUN/TAP device driver support
Other guff...
I'm still on openvpn 1.5.0 so these might be a little out of date on the new builds.
There was a reason I used tap instead of tun. I can't remember what it was sorry.
most configs in /etc/openvpn some in /etc/rc.d and build under the /usr/local/src tree
# my conf file on linux
dev tap
ifconfig 10.0.1.1 255.255.255.0
keysize 448
secret static.key
port 6001
comp-lzo
ping 15
verb 3
mute 5
I use the rc.d script from
# Contributed to the OpenVPN project by
# Douglas Keller <doug@voidstar.dyndns.org>
Put this in rc.local (I use slackware which has nice start scripts)
/etc/rc.d/rc.openvpn start
I always build these from the sources. It's generally the blindingly easy ./configure, make, make install sequence (which I read the READMEs to check).
On windows
remote xxx.xxx.xxx.xxx
port 6001
dev tap
ifconfig 10.0.0.2 255.255.255.0
secret static.key
keysize 448
ping 60
comp-lzo
verb 4
mute 10