For example, suppose we have the IPv6 address 2002:FF10:9876: DD0A:9090:4896:AC56:0E01/63 and we want to know what the network number is (host numbers are less useful in IPv6 networks, because they are often the MAC address of the system itself). 1  63 Ã£Â· 8 = 7, remainder 7. 2  The working octet is the 8th, which is 0A.