IP

“IPS” tab

NOTE
The IP protocol does not have a profile. Only a global configuration is available.

MTU

Impose MTU limit (force fragmentation)	MTU (Maximum Transmission Unit) represents the maximum size of an IP packet. If this option is selected, the next field will be enabled and you can define your limit.
Maximum MTU value	Define the maximum value of the IP datagram, between 140 and 65535 bytes.

Fragmentation

Minimum fragment size (bytes)	The fragment must be between 28 and 65535 bytes. The default value is 140 bytes.
Session will expire in (seconds)	This period must be between 2 and 30 seconds.

Stealth mode

Enable stealth mode

In stealth mode, the firewall does not respond to detection attempts - ICMP requests in particular - so that it appears invisible.
Stealth mode is enabled by default and can be disabled by unselecting this checkbox.

NOTE
Disabling stealth mode will affect packet processing performance.
As the firewall must keep a log of each packet so that it can respond to ICMP error messages,
stealth mode allows the firewall to save resources that would have been used on logging these packets.