Address groups are designed for ease of use in the administration of the device. If you have a number of addresses or address ranges that will commonly be treated the same or require the same security policies, you can put them into address groups, rather than entering multiple individual addresses in each policy refers to them.

The use of groups is not required. If you have a number of different addresses you could add them individually to a policy and the FortiGate firewall will process them just as quickly and efficiently as if they were in a group, but the chances are that if you have used a group once you could need to use it again and depending on the number of addresses involved entering them individually for each policy can become tedious and the likelihood of an address being missed becomes greater. If you have a number of policies using that combination of addresses it is much easier to add or subtract addresses from the group than to try and remember all of the firewall policies that combination of addresses was used in. With the group, you only have to make the one edit and it is used by any firewall policy using that address group.

Because security policies require addresses with homogenous network interfaces, address groups should contain only addresses bound to the same network interface, or to Any.

For example, if address 1.1.1.1 is associated with port1, and address 2.2.2.2 is associated with port2, they cannot be in the same group. However, if 1.1.1.1 and 2.2.2.2 are configured with an interface of Any, they can be grouped, even if the addresses involve different networks.

IPv4 address groups and IPv6 address groups are created and treated separately. You cannot mix IPv4 firewall addresses and IPv6 firewall addresses in the same address group. Because the Internet is currently based on IPv4 addresses IPv6 address groups cannot include FQDN or Geography based addresses.