This is a replacement for the vpnc-script used by OpenConnect or VPNC.

Instead of trying to copy the behavior of standard corporate VPN clients, which
normally reroute all your network traffic through the VPN, this one tries to
minimize your contact with an intrusive VPN. This is also known as a
split-tunnel VPN, since it splits your traffic between the VPN tunnel and your
normal network interfaces.

vpn-slice makes it easy to set up a split-tunnel VPN:
- By default, it only routes traffic for specific hosts or subnets through the
  VPN.
- It automatically looks up named hosts, using the VPN's DNS servers, and adds
  entries for them to your /etc/hosts (which it cleans up after VPN
  disconnection), however it does not otherwise alter your /etc/resolv.conf at
  all.
- It has many additional options to customize routing and lookup (for example,
  --route-splits to additionally route traffic for specific subnets requested by
  the server). Run vpn-slice --help to see them all.