[ale] Tunnel presistence connection issue

[ups at tree.com (Stephan Uphoff)]

On Thu, 2005-02-24 at 10:11, Christopher Fowler wrote:
> I'm using Vtun at a remote site and am running pppd inside my tunnel. 
> The remote site has Time Warner Cable as their provider.  After a few
> minutes of inactivity across the tunnel, the tunnel seems to lock up. 
> No data can go between the two machines.  Its as if something in between
> stopped the flow of traffic.  Eventually the tunnel will time out at the
> other end and close down and start a new one.  Out of 20+ sites this is
> the only site that does this.  Its also the only site using cable modem.
> Does anyone know what could be causing this?
> 
> Chris

Looks like a firewall (or nat router) issue to me.
( State information timing out due to inactivity)
PPP can test the link with ppp echo packets. (No need for IP pings)
This should keep our connection busy and alive.