2023-06-21 17:57:46 -06:00
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#!/bin/bash
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# Default values
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2024-02-25 11:40:00 -07:00
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dns_server=""
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2023-06-21 17:57:46 -06:00
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query_domain=""
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warning_time=200
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critical_time=250
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# Parse flag arguments
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while getopts "s:d:w:c:" flag; do
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case "${flag}" in
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s) dns_server="${OPTARG}" ;;
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d) query_domain="${OPTARG}" ;;
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w) warning_time="${OPTARG}" ;;
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c) critical_time="${OPTARG}" ;;
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*)
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echo "Usage: $0 -s <dns_server> -d <query_domain> -w <warning_time> -c <critical_time>"
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exit 1
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;;
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esac
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done
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2024-02-25 11:40:00 -07:00
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if [[ -z $query_domain && ${query_domain+x} ]]; then
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echo "Error: query domain not provided."
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2023-06-21 17:57:46 -06:00
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echo "Usage: $0 -s <dns_server> -d <query_domain> -w <warning_time> -c <critical_time>"
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2024-02-28 14:13:33 -07:00
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exit 3
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2023-06-21 17:57:46 -06:00
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fi
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# Perform DNS resolution check and measure the time
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2024-02-25 15:35:14 -07:00
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start_time=$(date +%s)
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2024-02-25 11:40:00 -07:00
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if [[ -z "$dns_server" ]]; then
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# The DNS server was not provided.
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result=$(dig "$query_domain" +short)
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dns_server="the default server"
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else
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result=$(dig @$dns_server "$query_domain" +short)
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fi
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2024-02-25 15:35:14 -07:00
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end_time=$(date +%s)
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response_time=$((end_time - start_time))
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2023-06-21 17:57:46 -06:00
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perfdata="response_time=${response_time}ms;${warning_time};${critical_time};0;"
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# Check response time against warning and critical levels
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2024-02-25 18:59:35 -07:00
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if [ -z "$result" ] || echo "$result" | grep -Eq "(no servers could be reached|communications error)"; then
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2024-07-25 19:40:14 -06:00
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echo "CRITICAL - DNS resolution failed for $query_domain on $dns_server"
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2023-06-21 17:57:46 -06:00
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exit 2
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elif [ "$critical_time" -gt 0 ] && [ "$response_time" -gt "$critical_time" ]; then
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echo "CRITICAL - DNS resolution took ${response_time}ms for $query_domain on $dns_server | $perfdata"
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exit 2
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elif [ "$warning_time" -gt 0 ] && [ "$response_time" -gt "$warning_time" ]; then
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echo "WARNING - DNS resolution took ${response_time}ms for $query_domain on $dns_server | $perfdata"
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exit 1
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else
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echo "OK - resolved $query_domain to $result using $dns_server in ${response_time}ms | $perfdata"
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exit 0
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fi
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