Simple definition
A FortiGate address object is a reusable object that represents an IP address, subnet, address range, FQDN, or another supported address type.
Technical definition
In FortiOS, address objects give a logical name to network sources or destinations that can then be referenced by firewall policies and address groups. The object type determines how FortiGate interprets its value, such as IPv4/IPv6 subnet, range, or FQDN.
How it works / role
Its role is to separate security rules from hard-coded IP values. A change to the object can therefore be reflected wherever that object is referenced, improving readability and maintenance.
What is it used for?
Build clearer firewall policies, group multiple networks, represent a server or domain, and reuse the same definition across several rules.
Practical example
The SRV-ERP object represents 192.168.20.15/32. Several policies use it as a destination; if the server address changes, the administrator updates the object instead of editing every policy separately.
Common issues
- Incorrect subnet mask or address range
- FQDN does not resolve as expected
- Object changed without checking every policy that references it
- Duplicate objects created for the same underlying resource
Key takeaway: Before changing or deleting an address object, review its references to avoid unintended effects on security policies.