CentOS - Apr 2013 - OpenVPN routing question

Hello all,

Let's say I have an OpenVPN (v2) server sitting on a Linux machine with the
IP address of, say, 192.168.10.1o. We are talking real address, assigned to
a NIC on the machine.

Now let us say the OpenVPN server hands out IP's in the
192.168.20.0/24range. And let us say that I want the machines able to
reach the VPN server
to be able to route to the machines available via the VPN. So, for
instance, 192.168.10.5 should be able to ping 192.168.20.6 assuming the
latter is one of the VPN clients.

So here is my question: is there a VPN setting that would facilitate that?
It seems like is is trivial enough to allow the VPN clients to route out
through the VPN server - but trying to facilitate the reverse I got stuck.

Thanks in advance for any help.

Cheers,

Boris.

On Sun, Apr 14, 2013 at 09:00:16AM -0400, Boris Epstein
wrote:
> Let's say I have an OpenVPN (v2) server sitting on a Linux machine with
the
> IP address of, say, 192.168.10.1o. We are talking real address, assigned to
> a NIC on the machine.
> 
> Now let us say the OpenVPN server hands out IP's in the
> 192.168.20.0/24range. And let us say that I want the machines able to
> reach the VPN server
> to be able to route to the machines available via the VPN. So, for
> instance, 192.168.10.5 should be able to ping 192.168.20.6 assuming the
> latter is one of the VPN clients.
> 
> So here is my question: is there a VPN setting that would facilitate that?
In the server config file
  push "route 192.168.10.0 255.255.255.0"

That will tell the openvpn client to add a route to 192.168.10.0/24 via
the openvpn gateway.

Machines on the LAN also need a route to 192.168.20.0/24 via the gateway;
this is easy if your OpenVPN server is also your default gateway (eg
router); otherwise you may need to add routes per-machine or via DHCP,
or potentially just tell the default router about the route and let it
send redirects to the LAN machines.

-- 

rgds
Stephen