How to enable subnet overlapping on a Fortigate
A short and sweet problem/resolution. If you are looking to enable subnet overlapping on a Fortigate so that you can give multiple interfaces an IP in the same subnet, this is the post for you. NOTE: This feature can only be enabled in the Fortigate’s CLI. To enable the overlapping feature, enter the following commands: config system settings set allow-subnet-overlap [enable/disable] end What is subnet overlapping? Subnet overlapping is disabled by default in fortiOS and for good reason; if you misuse subnet overlapping it can cause massive routing issues for your clients and their traffic. Subnet overlapping lets you apply IPs from the same subnet (e.g 192.160.1.X/24) to multiple interfaces that are not in the same virtual/physical switch. ...