Re: [Openvpn-devel] IP adress assignment to tun devices using server mode

[Denis V. <vd...@po...>]

On Monday 14 June 2004 20:49, James Yonan wrote:
> Torge Szczepanek <ope...@sz...> said:
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> > Hi!
> >
> > I am currently trying out OpenVPN 2.0 beta 4 using server mode.
> >
> > My config on the server looks like this:
> >
> > dev tun
> > mode server
> > ifconfig 192.168.100.1 192.168.100.2
> > ifconfig-pool 192.168.100.4 192.168.100.254
> > push "route 192.168.100.1 255.255.255.255"
> > route 192.168.100.0 255.255.255.0
> > [...]
> >
> > Everything works fine as expected. (Which is really great. I appreciate
> > the good work done here)
> >
> > I am wondering why there is a subnet of size /30 assigned to the client.
> > I would expect a Point-to-Point device to receive only one ip adress and
> > not a /30 subnet.
>
> This is done for the benefit of OSes (such as Windows) which don't support
> true point-to-point tun interfaces.
>
> The Windows TAP-Win32 driver supports tun interface emulation only.  What
> that means is that the driver can talk to tun interfaces on other OSes, but
> from the perspective of Windows, it sees the tun interface as a virtual
> ethernet interface having a subnet mask of 255.255.255.254, containing the
> two point-to-point interfaces, a network address, and a broadcast address.

255.255.255.252 (252 == 0xFC == 11111100 binary)
--
vda