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I've upgraded my iMac to Lion and that broke my VPN to work (Check Point's Connectra SNX--it's browser-based, so it does not use OS X built-in VPN). Long story short, until there's a fix, I want to share my MacBook Pro's VPN connection (still running Snow Leopard with VPN working) with my iMac.

I have the iMac connected to the MBP via ethernet and can share the MBP's internet connection with no problem. However, the iMac's internet traffic is not funneled into the VPN.

I've tried many hints, but none seem to work for me.

Using ifconfig, I see that the VPN creates and uses en7 for its traffic.

ifconfig before starting the VPN:

lo0: flags=8049<UP,LOOPBACK,RUNNING,MULTICAST> mtu 16384
inet6 ::1 prefixlen 128 
inet6 fe80::1%lo0 prefixlen 64 scopeid 0x1 
inet 127.0.0.1 netmask 0xff000000 
inet6 fdde:8fdc:2714:603c:217:f2ff:fec5:5844 prefixlen 128 

gif0: flags=8010<POINTOPOINT,MULTICAST> mtu 1280

stf0: flags=0<> mtu 1280

en0: flags=8863<UP,BROADCAST,SMART,RUNNING,SIMPLEX,MULTICAST> mtu 1500
ether 00:17:f2:c5:58:44 
inet 192.168.2.1 netmask 0xffffff00 broadcast 192.168.2.255
media: autoselect
status: inactive

fw0: flags=8863<UP,BROADCAST,SMART,RUNNING,SIMPLEX,MULTICAST> mtu 2030
lladdr 00:17:f2:ff:fe:8d:62:00 
media: autoselect <full-duplex>
status: inactive

en1: flags=8863<UP,BROADCAST,SMART,RUNNING,SIMPLEX,MULTICAST> mtu 1500
ether 00:17:f2:e6:e1:df 
inet6 fe80::217:f2ff:fee6:e1df%en1 prefixlen 64 scopeid 0x6 
inet 10.0.1.6 netmask 0xffffff00 broadcast 10.0.1.255
media: autoselect
status: active

And after starting the VPN:

lo0: flags=8049<UP,LOOPBACK,RUNNING,MULTICAST> mtu 16384
inet6 ::1 prefixlen 128 
inet6 fe80::1%lo0 prefixlen 64 scopeid 0x1 
inet 127.0.0.1 netmask 0xff000000 
inet6 fdde:8fdc:2714:603c:217:f2ff:fec5:5844 prefixlen 128 

gif0: flags=8010<POINTOPOINT,MULTICAST> mtu 1280

stf0: flags=0<> mtu 1280

en0: flags=8863<UP,BROADCAST,SMART,RUNNING,SIMPLEX,MULTICAST> mtu 1500
ether 00:17:f2:c5:58:44 
inet 192.168.2.1 netmask 0xffffff00 broadcast 192.168.2.255
media: autoselect
status: inactive

fw0: flags=8863<UP,BROADCAST,SMART,RUNNING,SIMPLEX,MULTICAST> mtu 2030
lladdr 00:17:f2:ff:fe:8d:62:00 
media: autoselect <full-duplex>
status: inactive

en1: flags=8863<UP,BROADCAST,SMART,RUNNING,SIMPLEX,MULTICAST> mtu 1500
ether 00:17:f2:e6:e1:df 
inet6 fe80::217:f2ff:fee6:e1df%en1 prefixlen 64 scopeid 0x6 
inet 10.0.1.6 netmask 0xffffff00 broadcast 10.0.1.255
media: autoselect
status: active

en7: flags=8863<UP,BROADCAST,SMART,RUNNING,SIMPLEX,MULTICAST> mtu 1350
ether 54:55:43:44:52:00 
inet 10.158.60.108 netmask 0xfffffc00 broadcast XXX.XXX.XXX.XXX
Check Point Virtual Network Adapter

And we see en7 is new.

I then followed an example and attempted the following (all with sudo):

natd -interface en7
ipfw -f flush
ipfw add divert natd ip from any to any via en7
ipfw add pass all from any to any

I already have IP Forwarding set to 1 in the conf file.

Whenever I issue the natd -interface en7 command (via sudo), I get the following:

natd: Unable to bind divert socket.: Address already in use

This occurs with all interfaces.

Does anyone know what I'm doing wrong and would anyone be able to walk me through this?

Any and all help would be greatly appreciated!

Thanks! james

share|improve this question
    
James - is your VPN using L2TP? If so, you can't use level 3 network routing commands to get around a level 2 pipe. Your VPN policy likely prevents what you ask. –  bmike Aug 2 '11 at 16:58
    
As far as I know, it is not using L2TP...at least not through OS X' built-in VPN. –  james Aug 2 '11 at 19:19

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