Re: [Openvpn-users] openvpn and voip

[Giancarlo Razzolini <linux-fan@xxxxxxxxxxx>]

Eric "Skippy" Hope wrote:
> Hi all,
> 
> I'm hoping that someone has a clue that they can spare.
> 
> We're trying to use openvpn to secure voice over ip sessions from a
> software phone on a windows box and the voip server.  The openvpn part
> works beautifully (and is a joy to work with compared to other vpn
> techs).  The problem comes in when trying to make a call.  The session
> initiation portion of the call goes over the vpn just like it should
> (this is the sip portion, for those familier with voip).  Once the other
> end picks up the phone, the software phone tries to send the actual
> voice connection over the public IPs, ignoring the vpn.  This seems to
> have something to do with the Win TUN/TAP interface.
> 
> windows.ovpn file:
> 
> client
> dev tun
> proto udp
> remote re.mo.te.ip 1194
> resolv-retry infinite
> persist-key
> persist-tun
> ca "path\\to\\crt"
> cert "path\\to\\crt"
> key "path\\to\\key"
> comp-lzo
> verb 5
> tun-mtu 1500
> tun-mtu-extra 32
> 
> 
> It seems like the softphones (and we've tried 3 or 4, all showing the
> same behavior) are picking the ethernet interface by default somehow. 
> Is there an option either on the client or server end to influence how
> it routes traffic?  We've tried redirect-gateway and the traffic does
> use the vpn, but the client machine becomes unusable due to dhcp problems.
> 
> Hoping for a clue,
> 
> Eric
> 
> 
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> 
It seems that you have tree paths to follow. Keep using the
redirect-gateway option and setting up properly a dhcp server as it
exemplified on the how-to, try to take a look on the voip software you
are using to make it aware of the openvpn tun interface or use tap. I
believe that the easy way is by taping the interface.

-- 
Giancarlo Razzolini
Linux User 172199
Moleque Sem Conteudo Numero #002
Slackware Current
Snike Tecnologia em Informática
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