The ping Command — Network Connectivity Testing

Overview

ping is the most basic network diagnostic tool. It sends small packets (ICMP echo requests) to a target host and measures the response time. Use it to check whether a server is reachable and to measure network latency.

Basic Syntax

ping [options] hostname_or_IP

Common Usage

Ping a host

ping example.com

On Linux, this runs continuously until you press Ctrl+C. Sample output:

PING example.com (93.184.216.34) 56(84) bytes of data.
64 bytes from 93.184.216.34: icmp_seq=1 ttl=56 time=11.2 ms
64 bytes from 93.184.216.34: icmp_seq=2 ttl=56 time=10.8 ms
64 bytes from 93.184.216.34: icmp_seq=3 ttl=56 time=11.5 ms
^C
--- example.com ping statistics ---
3 packets transmitted, 3 received, 0% packet loss, time 2003ms
rtt min/avg/max/mdev = 10.800/11.166/11.500/0.286 ms

Send a specific number of pings

ping -c 5 example.com

The -c flag limits the number of packets sent. The command exits automatically after 5 pings.

Understanding the Output

Per-packet line

Field	Meaning
`64 bytes`	Size of the response packet
`icmp_seq=1`	Sequence number (tracks packet order)
`ttl=56`	Time to live — remaining hop count
`time=11.2 ms`	Round-trip time (latency) in milliseconds

Summary statistics

Metric	Meaning
packets transmitted	How many pings were sent
received	How many responses came back
packet loss	Percentage of packets that never returned
rtt min/avg/max/mdev	Round-trip time: minimum, average, maximum, and standard deviation

What the results mean

Result	Interpretation
Low latency (< 50ms)	Good connection
High latency (> 200ms)	Slow connection, possibly distant server or congestion
0% packet loss	Stable connection
Partial packet loss	Intermittent connectivity issue
100% packet loss	Host unreachable, down, or blocking ICMP
“Request timed out”	No response received within the timeout

Useful Flags

Flag	Description
`-c N`	Send N packets then stop
`-i N`	Wait N seconds between pings (default: 1)
`-W N`	Timeout in seconds for each response
`-s SIZE`	Set packet size in bytes (default: 56)
`-q`	Quiet mode — only show summary
`-f`	Flood ping (requires root) — sends packets as fast as possible
`-4`	Force IPv4
`-6`	Force IPv6

IPv6 Testing with ping6

To test IPv6 connectivity:

ping -6 example.com
# or on older systems:
ping6 example.com

Practical Examples

Quick connectivity check

ping -c 4 yourdomain.com

Check if DNS is working (ping an IP vs. a domain)

ping -c 3 8.8.8.8           # Google's DNS IP — tests raw connectivity
ping -c 3 google.com        # Tests connectivity AND DNS resolution

If the IP works but the domain doesn’t, you have a DNS issue.

Test with a larger packet size

ping -c 5 -s 1400 example.com

Useful for detecting MTU (Maximum Transmission Unit) issues.

Troubleshooting Tips

100% packet loss doesn’t always mean the host is down — many servers and firewalls block ICMP (ping) traffic for security reasons.
If ping fails but your website loads, ICMP is likely blocked — this is normal.
Use traceroute or mtr for more detailed path analysis when ping shows high latency or packet loss.
Compare pings from your local machine to pings from the server itself to isolate whether the issue is on the network path or on the server.