ping for connectivity testing in Linux CLI - Step-by-Step Execution

Concept Flow - ping for connectivity testing

Start ping command

↓

Send ICMP Echo Request

↓

Wait for Echo Reply

↓

Receive Reply?

No→Timeout or Error

Yes↓

Display reply info

↓

Repeat or Stop

↓

End ping command

The ping command sends a small message to a target computer and waits for a reply to check if it is reachable.

Execution Sample

Linux CLI

ping -c 3 example.com

Send 3 ping requests to example.com and show the replies.

Execution Table

Step	Action	Packet Number	Result	Output
1	Send ICMP Echo Request	1	Reply received	64 bytes from example.com: icmp_seq=1 ttl=56 time=20 ms
2	Send ICMP Echo Request	2	Reply received	64 bytes from example.com: icmp_seq=2 ttl=56 time=21 ms
3	Send ICMP Echo Request	3	Reply received	64 bytes from example.com: icmp_seq=3 ttl=56 time=19 ms
4	Summary	-	-	3 packets transmitted, 3 received, 0% packet loss, time 2002ms rtt min/avg/max/mdev = 19.000/20.000/21.000/0.816 ms

💡 All 3 packets received replies, ping command ends after sending 3 requests.

Variable Tracker

Variable	Start	After 1	After 2	After 3	Final
packets_sent	0	1	2	3	3
packets_received	0	1	2	3	3
packet_loss_percent	0%	0%	0%	0%	0%

Key Moments - 3 Insights

Why does ping send multiple packets instead of just one?

Sending multiple packets (see execution_table rows 1-3) helps check consistent connectivity and measure average response time.

What does it mean if no reply is received for a packet?

If no reply is received (not shown here), ping reports a timeout or packet loss, indicating possible network issues (see exit_note).

Why is the summary important at the end?

The summary (execution_table row 4) shows overall success, packet loss, and timing, giving a clear picture of network health.

Visual Quiz - 3 Questions

Look at the execution table, how many packets were sent before the ping command ended?

A 3

B 1

C 0

D 4

💡 Hint

Check the 'packets_sent' variable in variable_tracker after the final step.

At which step does the ping command show the summary of results?

A Step 1

B Step 3

C Step 4

D Step 2

💡 Hint

Look at the 'Action' column in execution_table for the summary row.

If the second packet did not receive a reply, how would 'packets_received' change after step 2?

A It would be 2

B It would be 1

C It would be 0

D It would be 3

💡 Hint

Refer to variable_tracker and consider what happens when a reply is missing.

Concept Snapshot

ping command sends ICMP echo requests to test if a host is reachable.
Use '-c' option to limit number of packets.
Each reply shows response time and packet info.
Summary shows packets sent, received, loss %, and timing.
No reply means possible network problem or host down.

Full Transcript

The ping command helps check if a computer or website is reachable by sending small messages called ICMP echo requests. Each request waits for a reply. If a reply comes back, it shows the time taken. The command usually sends multiple packets to check consistency. At the end, it summarizes how many packets were sent, how many replies were received, the percentage of lost packets, and timing details. If no reply is received, it may mean the target is offline or there is a network problem. This visual trace showed sending 3 packets to example.com, all replied successfully, and the summary confirmed 0% packet loss.