ping is the simplest and most widely used network diagnostic tool. It sends ICMP Echo Request packets to a target and listens for Echo Replies — telling you whether the host is reachable and how long the round trip takes.
ICMP · RTT · Packet Loss · Linux · macOS · Windows
01 — How It Works
ping sends an ICMP Echo Request to the target host. If reachable, the host returns an ICMP Echo Reply. The time between sending and receiving is the round-trip time (RTT), measured in milliseconds.
ping is your first line of diagnosis — if you can't ping it, you can't reach it. If you can ping it but the service is down, the problem is above the network layer.
By default, ping runs continuously on Linux/macOS (stop with Ctrl+C) and sends 4 packets on Windows.
02 — Basic Usage
Linux / macOS
ping google.com
Windows
ping google.com
Typical output
PING google.com (142.250.185.46): 56 data bytes
64 bytes from 142.250.185.46: icmp_seq=0 ttl=117 time=12.4 ms
64 bytes from 142.250.185.46: icmp_seq=1 ttl=117 time=11.9 ms
64 bytes from 142.250.185.46: icmp_seq=2 ttl=117 time=12.1 ms
--- google.com ping statistics ---
3 packets transmitted, 3 received, 0% packet loss
round-trip min/avg/max/stddev = 11.9/12.1/12.4/0.2 ms
| Field | Meaning |
|---|---|
| icmp_seq | Sequence number — gaps indicate dropped packets |
| ttl | Time To Live remaining when packet arrived — lower = more hops |
| time | Round-trip time in milliseconds |
| packet loss | Percentage of sent packets that got no reply |
| min/avg/max/stddev | RTT statistics across all probes |
03 — Common Flags
| Flag | Linux / macOS | Windows |
|---|---|---|
| Count | -c <n> | -n <n> |
| Interval (sec) | -i <sec> | — |
| Packet size (bytes) | -s <bytes> | -l <bytes> |
| Timeout (sec) | -W <sec> | -w <ms> |
| TTL value | -t <ttl> | -i <ttl> |
| Force IPv4 | -4 | -4 |
| Force IPv6 | -6 | -6 |
| Flood ping | -f (root only) | — |
04 — Practical Examples
Send exactly 5 packets
ping -c 5 google.com # Linux / macOS
ping -n 5 google.com # Windows
Larger packet size — test MTU / fragmentation
ping -s 1400 google.com # Linux / macOS
ping -l 1400 google.com # Windows
Ping with 1-second interval continuously
ping -i 1 google.com
Fast flood ping (root required)
sudo ping -f -c 1000 192.168.1.1
Force IPv6
ping6 ipv6.google.com # Linux / macOS
ping -6 ipv6.google.com # Windows
05 — Interpreting Results
| What you see | What it means |
|---|---|
| 0% packet loss, low RTT | Host is reachable and the path is healthy |
| 0% loss, high RTT (>100 ms) | Host is reachable but the link is slow or congested |
| Intermittent loss (<10%) | Unstable link — check cables, Wi-Fi signal, or ISP |
| High loss (>10%) | Serious link problem — congestion, failing hardware, or QoS dropping ICMP |
| 100% loss, no reply | Host is down, ICMP is blocked by a firewall, or routing is broken |
| High stddev in RTT | Jitter — problematic for VoIP and real-time applications |
| TTL expired in transit | Routing loop or max hops exceeded |
⚠ A host that doesn't reply to ping is not necessarily down — many servers and firewalls block ICMP Echo Requests. Use traceroute or a port check to confirm.
ℹ For continuous monitoring with statistics, consider mtr — it combines ping and traceroute into a live view per hop.