https://stackoverflow.com/questions/21981796/cannot-ping-aws-ec2-instance
Add a new EC2 security group inbound rule:
- Type: Custom ICMP rule
- Protocol: Echo Request
- Port: N/A
- Source: your choice (I would select Anywhere to be able to ping from any machine)
Function: Send ICMP ECHO_REQUEST to network hosts
Syntax: ping [-aAbBdDfhLnOqrRUvV6] [-c count] [-F...
