4.1.1 IP address ranges
In the access control lists below, host ranges can be specified in a
number of ways i) as substrings, ii) as address ranges denoted by the
"-" hyphen, or iii) as CIDR (Classless Inter Domain Routing) notation.
In the CIDR notation, the slash followed by a number indicates the
netmask, or the number of bits which are common to a group of hosts.
Normally, this is connected to a specific subnet, but here it simply
represents the number of bits from the left which are fixed for matching;
all remaining bits are wildcards.
The following forms are equivalent: