Routing all traffic except a few IP-ranges though default gateway in Mountain Lion I am using VPN (Cisco IPSec) through the default Mountain Lion network preferences. In Lion (and also in Snow Leopard), I did the following to change the routing back to using my default gateway for all traffic, and thne set up a few routes for the specific IP-ranges that needed to go through VPN:

# Route traffic through VPN:
route -nv add -net IPRANGE -interface utun0
#...more lines for the different IP-ranges that should go through VPN)

# Route all other traffic through the old default gateway:
route change default DEFAULT-GATEWAY-IP


This seems to not work under Mountain Lion. The (new implementation?) of Cisco IPSec seems to dynamically add a lot of routes to the routing table as I visit them in the browser.

I have debugged this a lot (pinging, traceroute'ing), but still haven't found a solution. 

The basic problem I'm trying to solve is just to route traffic for specific IP-ranges through VPN, everything else should act as I am not connected to VPN. Any other solution that achieves that will be fine with me =)
If you configure your VPN server to allow split tunneling, this will work without any need to configuree your vpn client or the network on the Mac. 


http://www.cisco.com/c/en/us/support/docs/security/anyconnect-secure-mobility-client/119006-configure-anyconnect-00.html



  Split-tunneling is used in scenarios where only specific traffic must be tunneled, opposed to scenarios where all of the client machine-generated traffic flows across the VPN when connected. Use of the AnyConnect Configuration Wizard will by default result in a tunnel-all configuration on the ASA. Split tunnelling must be configured separately, which is explained in further detail in the Split Tunnel section of this document.