[YLUG] VPN

[john halewood]

2009/7/18 Patrick Dupre <pd520 at york.ac.uk>:
> ping 213.205.96.91 does not respond any more,
> a ssh (back) on my machine does not work: eschyle.homedns.org (or
> 86.10.230.254)
> Destination     Gateway         Genmask         Flags   MSS Window  irtt
> Iface
> 0.0.0.0         0.0.0.0         0.0.0.0         U         0 0          0
> ppp0
 Typical VPN scenario - your default gateway after setting up the VPN
is to route all packets via the VPN iself, so your machine is
effectively inside the campus network, and all attempts to get to the
outside world will be subject to the campus firewall rules. I've had
this trouble in the past when setting up a VPN for a remote office in
Germany just so they could use a single application on a server in the
UK. Unfortunately, when they tried to use other apps (e.g. web
browser) it was horribly slow because the web traffic went up the VPN
out through the UK and then all the way back again. If all you want to
access via the VPN is apps on campus, then manipulate the routing
table to add the campus network via ppp0 and reinstate the default
(0.0.0.0) to go back through eth0. If you're running an X session over
the VPN you won't notice the difference, but it can cause problems in
other ways. Routing tables aren't by default that clever.

cheers
john
(back out of hospital which is why I've been a bit quiet recently)