Simple helper script to pass shell commands through an vpn network, that does not affect another local programs/services.
Setup all needed information into an small shell script like example.sh. General you can use any vpn client what you like / need.
Alternativ put all things into an single command line. That could look like followed lines for an vpnc setup with the vpnc configuration file vpn_network_001 (normally located at /etc/vpnc/vpn_network_001.conf).
env \
VPN_COMMAND="/usr/bin/vpnc vpn_network_001" \
VPN_SET_COMMAND_STOP="/usr/bin/vpnc-disconnect" \
VPN_SET_INTERFACE_CONNECT="eth0" \
VPN_SET_INTERFACE_VPN="vpn-001" \
./vpn-single-application.sh execute \
/usr/local/bin/....