Managing your cloud resources with OpenStack: Difference between revisions

An example of a CIDR rule is <code>192.168.1.1/24</code>. This looks just like a normal IP address with a <code>/24</code> appended to it. IP addresses are made up of 4, 1-byte (8 bit) numbers ranging from 0 to 255. What this <code>/24</code> means is that this CIDR rule will match the first left most 24 bits (3 bytes) of an IP address. In this case any IP address starting with <code>192.168.1</code> will match this CIDR rule. If <code>/32</code> is appended the full 32 bits are specified the IP address must match exactly, likely wise if a <code>/0</code> is appended no bits must match and therefore any IP address will match it.