Description
This article explains how to block some of the specific public IP addresses to enter the internal network of the FortiGate to protect the internal network. This is specific to configurations that already have inbound firewall policies allowing traffic internally to specific subnets that can be routable externally or that have a VIP as a destination. By default, traffic from external is not allowed internally without a firewall policy configured to allow externally initiated sessions.
Scope
FortiGate.
Solution
Step1: Create an address object
Go to Policy & Objects -> Addresses
Click on 'create new' and 'Address'
Name: Provide any name
Type: Subnet
Subnet / IP Range : x.x.x.x/32 where x.x.x.x is the specific public IP it is required to block
x.x.x.x/24 where x.x.x.x is the subnet it is required to block and /24 is the subnet
Click on 'OK' to apply the changes
Go to Policy & Objects -> IPv4 policy
Name: Provide any name
Incoming interface: WAN interface
Outgoing interface: LAN interface
Source: Select the address object, created above.
Destination: set it to "all"
Schedule: Always
Services: All
Action: Deny
NAT: Enable
Security Profiles:
Enable IPS
Note:
If a group of addresses requires to be blocked, select Addresses -> Address Group and select 'Create New'.
Related article:
Troubleshooting Tip: VIP traffic not matching the firewall policy with an 'all' destination
Note:
V5.0 up to v6.4 are out of engineering support. These GUI sections might be different in higher versions.
Consider upgrading the firmware level on the device to a supported version (v7.0 up to v7.6). Check the firmware path and compatibility depending on the hardware.
