Packet InterNet Groper (PING)
Well, PING is a type of special packet that is called as ICMP packets (internet control message protocol), in many monitoring system ICMP packets could be used today but someone learned to exploit the ICMP packet that how during ICMP process one can destroy servers and whole network. And that is how ICMP became security exploit. ICMP was game changer for future but was misused by people.
Almost 50% to 70% security attacks are executed during ICMP including very well know D-DOS attack. And hence, to end the almost 70% of the security attacks, decision was made to stop the ICMP packet and still today we can see that all security devices blocks the ICMP packet including the windows firewall as well.
The reason it wont check network connectivity by PING is that on every enterprise network there is a firewall, which will deny the ICMP packet. Why PING does not check the internet latency as well?
When we PING, it classify into data and according to quality of service (QOS) the prioritization is voice, video and then data, where data is least priority in QOS behind voice and video. And the reason for such priority is that this is how the data communication was meant to be treated, because data is not delay sensitive.
That is why PING will not show the network latency measurement, it will just show the data latency in the network. So if we have to check the actual latency of the whole network, what should we do?
There are special types of tools for example IP SLA by cisco which shows the accurate measurement of the network latency.
What is PING?
PING is a tool or an application which uses ICMP echo packets to get IP upper layer protocol stack information of a remote device. PING is available only on the IP upper layer protocol, it is not available on IPX and AppleTalk. We can also use PING for checking connectivity, calculating latency, calculating TTL (time to live). 100% enterprise network uses IP.
Upper layer protocol -
Me as a user cannot communicate with technology directly. There is a need of medium in between. There is a need of mediation layer, a software, a protocol that can become the medium through which the user can communicate with technology.
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Mapping -
Whenever we assign the IP address to the network (NIC) of any device, there are two table that initiates:
Network table -
When we assign IP, then the number of network cards and the assigned IPs are stored in a network table.
Network interface card (NIC) -
IPs are assigned to the NICs of devices, not devices. Every network card has a unique hardware address.
ARP table -
The assigned IP address will get mapped with the NIC's L2 address and together will be stored in the ARP table.
So! This was the brief explanation about PING and few related concepts. See you in the next article!