MacOS – Routing all traffic except a few IP-ranges though default gateway in Mountain Lion

I've had the same problem for a few months. I had to disconnect and had Internet access. Connect so I can have access to corporate resources.... A pain.

My temporary solution was to install a Sonatype Nexus (proxy for dependencies) under Debian Linux and connect with vpnc. Usually you can install it with apt-get/yum etc.

When this solution was not enough, I installed vpnc in my Windows machine with vpnc-fe http: // sourceforge.net/projects/vpncfe/ (VPNc Front-End) on top.

My configuration required a setting for perfect security called "Force-NTT". See this thread. Later you need to put the following script in postconnect.bat:

[Copy in case the thread goes down]

Thank you, rodekerken! Here's the final result, no manual tinkering necessary to break out the split routes:

@echo off
REM By: capt-tagon
REM 
REM Post-Script.bat to take VPNC's Route Table into Windows 7 land. Erases bad route table entries, 
REM extracts gateway, assigned IP, Netmask, and Cisco split route entries and resubmits them to 
REM Windows 7 so the routing all works. Condensed from other entries on the VPNC-FE forae and combined
REM with information gleaned from VPNC client for Linux to find all the passed parameters useful
REM to making this work. Additional by rodekerken noted below, thank you for helping finish it out.
REM
setlocal enabledelayedexpansion
echo.
echo Post-Script Begin
echo.
REM Gather Connection Data
REM 
REM Parameters passed have space at end, see "HELP SET" at Console Prompt for explanation of
REM substring extraction
REM Strip space from TUNDEV, INTERNAL_IP4_ADDRESS, VPNGATEWAY, CISCO_SPLIT_INC
REM This will be broken if VPNC-FE is fixed to not export parameters with the trailing space.
REM 
set MyTUNDev=%TUNDEV:~0,-1%
REM By: rodekerken
REM From the top of the router table printout, look for a line like
REM 14...00 ff 5d b0 44 aa ......TAP-Win32 Adapter V9 to find the if number.
REM A way to find out the interface number automatically and extractis this:
for /f "tokens=1 delims=." %%a in ('route print ^|find "TAP-Win32"') do set MyIF=%%a
set MyIP=%INTERNAL_IP4_ADDRESS:~0,-1%
set MyMask=%INTERNAL_IP4_NETMASK:~0,-1%
set MyVPN=%VPNGATEWAY:~0,-1%
REM Number of Routing Table Entries for Split Tunnel
set MyCiscoSplit=%CISCO_SPLIT_INC:~0,-1%
REM Date Time functions
set ANSIDate=%date:~10%%date:~4,2%%date:~7,2%
set StartTime=%time:~0,2%%time:~3,2%%time:~6,2%
REM Display Connection Data
echo Tunnel Device : [%MyTUNDev%]
echo Tunnel IntFace: [%MyIF%]
echo Tunnel IPAddr : [%MyIP%]
echo Tunnel NetMask: [%MyMask%]
echo Tunnel VPN-GW : [%MyVPN%]
echo .
echo Date Connected: [%ANSIDate%]
echo Time Connected: [%StartTime%]
echo .
REM Cisco Routes are 0 index, 6 Routes = 0-5
echo Cisco Split Routes: [%MyCiscoSplit%]
REM Display Bad Route Table
echo.
echo Bad Route Table
route print | find "%MyIP%"
echo.
REM Delete Bad Split Route entries and add back with proper Gateway.
REM Extract Cisco routing table information to feed to "ROUTE ADD"
REM Number of entries passed in Array Index CISCO_SPLIT_INC 
REM For x below, value is 0 to CISCO_SPLIT_INC - 1
REM Address is passed in CISCO_SPLIT_INC_x_ADDR
REM NetMask is passed in CISCO_SPLIT_INC_x_MASK
REM
REM By: rodekerken
REM A way to loop and enumerate and evaluate the routes is like this:
set /A MyCiscoSplit-=1
for /L %%i in (0,1,%MyCiscoSplit%) do (
                set SplitAddr=CISCO_SPLIT_INC_%%i_ADDR
                set SplitMask=CISCO_SPLIT_INC_%%i_MASK
        for /f %%a in ('echo !SplitAddr!') do set SplitAddrEval=!%%a!
        for /f %%a in ('echo !SplitMask!') do set SplitMaskEval=!%%a!
        echo Route%%i !SplitAddrEval! !SplitMaskEval!
        route delete !SplitAddrEval! >nul
        route add !SplitAddrEval! mask !SplitMaskEval! %MyVPN% metric 1 if %MyIF% >nul
)
REM Display Corrected Route Table
echo.
echo Corrected Route Table
route print | find "%MyVPN%"
echo.
echo Post-Script End
echo.

I've also added this routes after the "FOR":

route add 1111.120.120.0 mask 255.255.255.0 0.0.0.0 metric 1 if %MyIF%
route add 1111.185.19.0 mask 255.255.255.0 0.0.0.0 metric 1 if %MyIF%
route add 10.0.0.0 mask 255.0.0.0 0.0.0.0 metric 1 if %MyIF%

[Please note that the first two routes have incorrect/fake addresses. You need to change it anyway]

For my script to work repeatedly, you need to create a "disconnect.bat" containing the removal of routes:

route delete 1111.120.120.0
route delete 1111.185.19.0
route delete 10.0.0.0

Just my 0.02€

I think I found the problem. The explanations and possible solutions will be posted here: https://forums.openvpn.net/post28560.html#p28560.