Aus dem Handbuch:
Preventing the public interface from responding to ping
requests
The factory default configuration of your FortiGate unit allows the default public
interface to respond to ping requests. The default public interface is also called
the default external interface, and is the interface of the FortiGate unit that is
usually connected to the Internet.
For the most secure operation, you should change the configuration of the
external interface so that it does not respond to ping requests. Not responding to
ping requests makes it more difficult for a potential attacker to detect your
FortiGate unit from the Internet.
A FortiGate unit responds to ping requests if ping administrative access is
enabled for that interface. You can use the following procedures to disable ping
access for the external interface of a FortiGate unit. You can use the same
procedure for any FortiGate interface. You can also use the same procedure in
NAT/Route or Transparent mode.
To disable ping administrative access from the web-based manager
1 Log into the FortiGate web-based manager.
2 Go to System > Network > Interface.
3 Choose the external interface and select Edit.
4 Clear the Ping Administrative Access check box.
5 Select OK.
To disable ping administrative access from the FortiGate CLI
1 Log into the FortiGate CLI.
2 Disable administrative access to the external interface. Enter:
config system interface
edit external
unset allowaccess
end