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Re: [Openvpn-users] Route add fail with IPAPI and PPP.

  • Subject: Re: [Openvpn-users] Route add fail with IPAPI and PPP.
  • From: Leonard Isham <leonard.isham@xxxxxxxxx>
  • Date: Fri, 21 Jan 2005 22:18:36 -0500

On Fri, 21 Jan 2005 17:02:40 -0500, Andrew J. Richardson
<andrew@xxxxxxxxxxxxxxxxxxxxxxx> wrote:
> > Before I start digging into the problem that seems to occur
> > when OpenVPN
> > tries to add routes on Windows via IPAPI when using a PPP or PPPoE
> > adapter, there's something I'd like to have explained to me.
> >
> > I perfectly understand normal IP subnetting and routing, but I don't
> > understand exactly how PtP links work.
> >
> > I though on a PtP link you always have a local IP address and
> > a remote IP
> > address, like when you deal with tun interfaces and OpenVPN,
> > you specify
> > your local IP address, and the IP address on the remote end.
> > You can then
> > add routes over this PtP link by specifying the remote end IP
> > address as
> > gateway address.
> >
> > When dialing with a modem in windows, this does not seem to
> > be the case.
> > I'm assigned an IP address via PPP, with a netmask of
> >, but
> > I can't see any remote IP address, and the added default gw
> > points to my
> > own IP address.
> I'd like to know the answer to this, too, because it breaks using OpenVPN
> with the redirect-gateway option.
> If I use OpenVPN with the redirect-gateway directive on a typical LAN
> segment and redirect the gateway to my home machine I can tunnel everything
> through home just fine.
> If I use the directive when dialed to my cell provider's network (a PtP
> connection as Mathias described) the redirect fails at adding the first
> route (a direct route to my existing "gateway").  OpenVPN without the
> redirect-gateway directive works just fine, though.  I just can't redirect
> all my traffic to a remote gateway.


1. Connect using PPP or PPPoE.
2. traceroute/tracert to a system you have login access to.
3. Login to the system tou did the traceroute to.
4. Traceroute back to the IP address assigned to you by PPP/PPPoE
5. Do a nslookup on the  IP address assigned to you by PPP/PPPoE
6. Try to telnet to the  IP address assigned to you by PPP/PPPoE

I think you'll get a login prompt even if you are not runnig a telnet server.

Leonard Isham, CISSP 
Ostendo non ostento.

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