To further explain how to achieve split tunneling without any side effects:
Originally Posted by ThomasNovin
1. Add a route to the network you want to connect to. For example, you need to reach 172.30.0.0/24 through your SSL-VPN.
(just add it pointing to any active interface, it won't be used)
sudo route add -net 172.30.0.0/24 dev wlan0
2. Connect with Juniper NC
3. Note how NC has added a better-metric route to 172.30.0.0/24 pointing to the tunnel.
4. Replace your default route (change 10.0.0.254 to whatever your default gw is)
sudo route del default gw 10.0.0.254 ; sudo route add default gw 10.0.0.254 metric 0
You now have VPN access to 172.30.0.0/24 and the rest of the traffic will go out through your Internet connection as usual!
If you need local access to hosts on your network, you will need to do a replace on that route too.