This parameter specifies the host name or address of a RadSec server (the instance of Radiator with a ServerRADSEC clause) that this <AuthBy RADSEC> is to connect to. The address can be an IPv4 or IPv6 name or address. Multiple Host lines are supported, which is equivalent to specifying multiple <Host> clauses. Special formatting characters are supported.

Here is an example of using Host:

# Example Host lines for IPv4 and IPv6 addresses
Host 203.63.154.1
Host oscar.open.com.au
Host ipv6:your.ipv6.host.com
Host 2001:db8:1500:1::a100
# IPv6 loopback:
Host ::1