Information
The icmpaddressmask parameter determines whether the system responds to an ICMP address mask ping.
Rationale:
The icmpaddressmask parameter will be set to 0, This means that the system will not respond to ICMP address mask request pings. By default, when this is enabled the system is susceptible to source routing attacks. This is typically a feature performed by a device such as a network router and should not be enabled within the operating system.
Solution
In /etc/tunables/nextboot, add the icmpaddressmask entry:
no -p -o icmpaddressmask=0
This makes the change permanent by adding the entry into /etc/tunables/nextboot
Default Value:
1