Troubleshooting Tip: FortiGate becomes unresponsive and unable to ping anything

Description

This article describes an issue where FortiGate becomes unresponsive or is unable to ping anything.

Scope

FortiGate.

Solution

This behavior will occur when there are more than three 802.1ad interfaces configured on FortiGate.

For example, if more than three interfaces are configured with the following vlan-protocol, this issue may occur:

config system interface 
    edit 'interface_name'
        set vlan-protocol 8021ad
    next
end

This can also cause FortiGate to be unable to ping.

FGT(root) # execute ping 8.8.8.8
PING 8.8.8.8 (8.8.8.8): 56 data bytes

--- 8.8.8.8 ping statistics ---
5 packets transmitted, 0 packets received, 100% packet loss

This affects NP7Lite devices.
FortiGate NP7Lite architectures

The issue has been fixed in FortiOS v7.6.7 and v8.0.0.