Testing connectivity: ping

ping checks whether another machine is reachable and how long it takes to reply.

Syntaxping [-c count] host

ping is the first tool to reach for when the network seems broken. It sends small packets to a host and measures the round-trip time of the replies.

Reading the output

  • time= — the round trip in milliseconds; lower is better.
  • 0% packet loss — every packet returned; the link is healthy.

On Linux ping keeps going until you stop it with Ctrl+C. Use -c 4 to send just four packets and exit.

Example

Example · bash
# Send four packets then stop
ping -c 4 google.com
# 64 bytes from ...: time=12.3 ms
# 4 packets transmitted, 4 received, 0% packet loss

# Ping an IP address directly
ping -c 4 1.1.1.1

When to use it

  • A sysadmin runs 'ping -c 4 8.8.8.8' to verify internet connectivity after configuring a new server's network interface.
  • A network engineer uses 'ping -i 0.2 -c 100 192.168.1.1' to measure packet loss on a LAN link over many rapid samples.
  • A developer pings an internal service hostname to confirm DNS resolution is working before deploying an application.

More examples

Basic connectivity check

Uses -c 4 to send exactly 4 ICMP packets, avoiding an infinite ping, and reports round-trip time statistics.

Example · bash
# Send 4 packets then stop
ping -c 4 google.com
# PING google.com (142.250.80.46): 56 bytes
# 4 packets transmitted, 4 received, 0% packet loss
# rtt min/avg/max = 11.2/12.4/14.1 ms

Ping with custom interval

Uses -i to set the interval between packets; -f enables flood mode for high-rate stress testing.

Example · bash
# Ping every 0.2 seconds for 20 packets
ping -i 0.2 -c 20 192.168.1.1

# Flood ping (requires root) for stress testing
sudo ping -f -c 1000 192.168.1.1

Ping to check DNS and latency

Shows that ping implicitly tests DNS resolution and uses a loop to compare latency across multiple hosts.

Example · bash
# Ping resolves the hostname first, showing its IP
ping -c 2 api.example.com
# PING api.example.com (203.0.113.42): 56 bytes

# Compare latency to two endpoints
for host in api.example.com db.example.com; do
  echo -n "$host: "
  ping -c 3 -q "$host" | tail -1
done

Related

linux curl wgetlinux ip

Discussion

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