Ping is a utility which sends an ICMP "echo request" message to a machine, who, if it is supported and enabled, will reply back with the same packet that was sent to it. The inability to get a ping response from a server but still being able to connect to it using a TCP/IP connection is totally normal. Obviously, your server is set to not to respond to ICMP requests.
Blocking PING on the server is helpful sometimes if the server continues to face any type of DDoS attack by using the PING feature. By using iptables / CSF is a rule-based firewall system and is normally pre-installed on a Unix operating system which is controlling the incoming and outgoing packets rules set we can simply stop the PING option to and from your server.
These are two totally different services, and one, both, or neither could be enabled on any machine.
What you are probably seeing is that the machine you are connecting to has a web server running, but has ICMP requests disabled. Also, any number of firewalls could exist between you and this box, any of which could be filtering out ICMP traffic.
Finally, it is quite fine if some PING response fails due to ICMP traffic, you will not have any network issue at all.
Thursday, August 9, 2018
