OpenConnect (Cisco AnyConnect)

Install the networkmanager-openconnect package from the Official repositories

$ sudo pacman -S networkmanager-openconnect

Download a more up-to-date script that OpenConnect will use to setup routing and DNS information (the only difference, currently, between this script and the one that comes with vpnc is using /usr/sbin/resolvconf instead of /sbin/resolvconf, there should be an AUR package for this eventually):

# wget http://git.infradead.org/users/dwmw2/vpnc-scripts.git/blob_plain/HEAD:/vpnc-script

Replace references to /sbin/resolvconf with /usr/bin/resolvconf:

$ sed -i 's/\/sbin\/resolvconf/\/usr\/bin\/resolvconf/g' vpnc-script

Make it executable:

$ chmod +x vpnc-script

Now run OpenConnect as root with the script downloaded above, and provide the gateway:

$ sudo openconnect --script ./vpnc-script https://vpn.system.com

It will ask you to enter GROUP Name:

Please enter your username and password.
GROUP: [User|Manager]: 

then,

Please enter your username and password.
Username:
Password:

Use ctrl-c to close and tear down the vpn connection.