How to check if ICMP blocking is enabled in a system..?

Question

A VLAN pool enabled newly is not pinging the device. Connectivity issues are not there.

• Can this be because if ICMP Blocking is enabled?
• How to check the status of the same?

Answer 1

To check whether ICMP is enabled or disabled run the command:

cat /proc/sys/net/ipv4/icmp_echo_ignore_all

The output is 0 or 1:

• 0 means that ICMP is enabled
• 1 means that ICMP is disabled

If it's disabled and you want to enable it:

• change 1 to 0 in the above file

• Or run the command:

  iptables  -I  INPUT  -i  ech0  -p   icmp  -s  0/0  -d  0/0   -j  ACCEPT