The other day I needed to setup a remote VPN connection back to my colocated environment and found that after setting up the VPN with l2tp I was unable to connect to any hosts. I quickly realized that I needed to setup static routes… so I dug around and found a great article by Rob Allen.
To solve this, you simply need to do the following on your Mac.
sudo touch /etc/ppp/ip-up sudo chmod 755 /etc/ppp/ip-up vi /etc/ppp/ip-up
#!/bin/sh /sbin/route add -net 172.16.33.0/24 -interface ppp0 /sbin/route add -net 10.0.21.0/24 -interface ppp0