Subnet::IPv6::Unspecified

The address with all zero bits is called the unspecified address (corresponding to 0.0.0.0 in IPv4). It should be something like this:

0000:0000:0000:0000:0000:0000:0000:0000

but, with the use of compression, it is usually written as just two colons:

::

or, specifying the netmask:

::/128

With Subnet, create a new unspecified IPv6 address using its own subclass:

ip = Subnet::IPv6::Unspecified.new

ip.to_s
# => => "::/128"

You can easily check if an IPv6 object is an unspecified address by using the IPv6#unspecified? method

ip.unspecified?
# => true

An unspecified IPv6 address can also be created with the wrapper method, like we've seen before

ip = Subnet.parse "::"

ip.unspecified?
# => true

This address must never be assigned to an interface and is to be used only in software before the application has learned its host's source address appropriate for a pending connection. Routers must not forward packets with the unspecified address.

ip = Subnet::IPv6::Loopback.new

ip.to_string
# => "::1/128"