Ping Monitor Shell Script Linux

Ping monitor scripts are still searched constantly for home labs, branch routers, and tunnel endpoints — simpler than SNMP for “is the other side alive?” This version alerts only on sustained failure and respects a cooldown.

What this script does

Pings a host N times with timeout
Treats 100% loss as DOWN
Emails on transition to down (with cooldown)
Logs every check for post-mortems
Works with IPv4 hostnames or IPs

Prerequisites

iputils-ping or busybox ping
ICMP allowed from server to target
mailx for alerts (optional)

Step 1: Save the script

sudo nano /usr/local/bin/ping-monitor.sh
sudo chmod +x /usr/local/bin/ping-monitor.sh

Step 2: Full script (scroll to read)

ping-monitor.sh

#!/usr/bin/env bash
set -euo pipefail

HOST="${1:?usage: ping-monitor.sh HOST}"
COUNT="${PING_COUNT:-3}"
ALERT_TO="${ALERT_TO:[email protected]}"
COOLDOWN_SEC=600
STATE="/var/run/ping-monitor-${HOST//\//_}.state"
LOG="/var/log/ping-monitor.log"

log(){ echo "[$(date '+%F %T')] $HOST $*" | tee -a "$LOG"; }

if ping -c "$COUNT" -W 2 "$HOST" >/dev/null 2>&1; then
  log "UP"
  echo up >"$STATE"
  exit 0
fi

log "DOWN (${COUNT} packets lost)"
prev=$(cat "$STATE" 2>/dev/null || echo up)
now=$(date +%s)
last_alert=$(cat "${STATE}.alert" 2>/dev/null || echo 0)

if [[ "$prev" == down ]] && (( now - last_alert < COOLDOWN_SEC )); then
  log "SKIP alert (cooldown)"
  exit 1
fi

{
  echo "Host $HOST appears DOWN from $(hostname -f)"
  ping -c "$COUNT" "$HOST" || true
} | mail -s "[ping] $HOST down" "$ALERT_TO" 2>/dev/null || log "mail failed (no MTA?)"

echo down >"$STATE"
echo "$now" >"${STATE}.alert"
exit 1

Scroll inside the box to read the full script.

Step 3: Configure settings

Some clouds block ICMP — use TCP check script instead for public endpoints
See wait-for-port script for deploy gates
Uptime HTTP checks: website uptime script

Ping monitor shell script alerting when host is down

Step 4: Test manually

./ping-monitor.sh 127.0.0.1

./ping-monitor.sh 192.0.2.1

Schedule with cron

sudo crontab -e

Add:

* * * * * /usr/local/bin/ping-monitor.sh vpn-gateway.example.com >> /var/log/ping-monitor.log 2>&1

Ping Monitor Shell Script for Linux (Host Down Alert, Cron)