Through Command Line

run 

sudo openconnect vpn.cites.illinois.edu

You should see a prompt that looks like 

GROUP: [1_SplitTunnel_Default|2_SplitTunnel_2FA_Duo|3_TunnelAll|4_TunnelAll_2FA_Duo|5_SplitTunnel_NoPrivate|6_SplitTunnel_NoPrivate_2FA]:


type

1_SplitTunnel_Default or 3_TunnelAll

and hit enter. then enter your netid and password when prompted.

SplitTunnel will forward all traffic to illinois domains over the VPN, and route all other traffic through your normal internet connection. TunnelAll will forward all traffic through the VPN. The “_duo” involve two-factor authentication, which is not required for most accounts.

Through the Gnome Network Manager (Using Ubuntu Gnome 16.04)

First, install the openconnect component for the network manager.

    sudo apt install network-manager-openconnect network-manager-openconnect-gnome

Click the ‘+’ icon in the lower-left of the network manager, and add a “VPN” network. Choose “Cisco AnyConnect Compatible VPN (openconnect)”

For Name, enter anything (“Illinois”). For Gateway, enter “vpn.cites.illinois.edu”

Hit add.

Now, when you use the network manager to connect to the VPN, you can enter your netid, password, and choose the group like above. You can save the authentication information so you don’t have to retype it every time.

Using the default Unity desktop environment is probably similar.