dnstest.sh

#!/usr/bin/env bash

command -v bc > /dev/null || { echo "bc was not found. Please install bc."; exit 1; }
{ command -v drill > /dev/null && dig=drill; } || { command -v dig > /dev/null && dig=dig; } || { echo "dig was not found. Please install dnsutils."; exit 1; }

# Function to calculate median
calculate_median() {
    local sorted=($(printf '%s\n' "$@" | sort -n))
    local length=${#sorted[@]}
    local mid=$((length / 2))
    if [ $((length % 2)) -eq 0 ]; then
        echo "scale=2; (${sorted[mid-1]} + ${sorted[mid]}) / 2" | bc
    else
        echo "${sorted[mid]}"
    fi
}



NAMESERVERS=`cat /etc/resolv.conf | grep ^nameserver | cut -d " " -f 2 | sed 's/\(.*\)/&#&/'`

PROVIDERS="
1.1.1.1#cloudflare 
8.8.8.8#google 
9.9.9.9#quad9 
45.90.28.0#NextDNS
103.247.36.36#DNSFilter
76.76.2.0#ControlD
4.2.2.1#level3 
208.67.222.123#Cisco
80.80.80.80#freenom 
208.67.222.123#opendns 
199.85.126.20#norton 
185.228.168.168#cleanbrowsing 
77.88.8.7#yandex 
156.154.70.3#neustar 
"

# Domains to test. Duplicated domains are ok
DOMAINS2TEST="kagi.com google.com facebook.com yahoo.com amazon.com ibm.com microsoft.com apple.com medium.com cnn.com foxnews.com bild.de nytimes.com mateja.prelovac.com enigma.rs hmdt.jp podravka.hr argentia.com.ar bildung.sachsen.de orionfeedback.org unknowndomain1233.com womenoftoday.com unionsforenergydemocracy.org adaniairports.com labola.es christopherfowler.co.uk groupe-ecomedia.com 12noon.com michaelasseff.net intfiction.org headhunter-blog.de dorure.fr hookedonphonics.us annhamiltonstudio.com sv-mistelgau.de heimat-berlin.com sdreadytowork.com leadabatementproducts.com goingonanadventure.co.uk junkfood.com noncense.org teclis.com igotthiswrongsdklf.com sundayhome.brb"

totaldomains=0
# Print markdown table header
printf "| %-16s |" "DNS Provider"
for d in $DOMAINS2TEST; do
    totaldomains=$((totaldomains + 1))
    printf " %-7s |" "test$totaldomains"
done
printf " %-7s |" "Average"
echo ""

# Print markdown table separator with alignment
printf "|:%-16s:|" "-----------------"
for ((i=1; i<=totaldomains; i++)); do
    printf ":%-7s:|" "--------"
done
printf ":%-7s:|" "--------"
echo ""

results=()

for p in $NAMESERVERS $PROVIDERS; do
    pip=${p%%#*}
    pname=${p##*#}
    ftime=0
    times=()

    printf "| %-16s |" "$pname"
    for d in $DOMAINS2TEST; do
        ttime=`$dig +tries=1 +time=2 +stats @$pip $d |grep "Query time:" | cut -d : -f 2- | cut -d " " -f 2`
        if [ -z "$ttime" ]; then
            #let's have time out be 1s = 1000ms
            ttime=1000
        elif [ "x$ttime" = "x0" ]; then
            ttime=1
        fi

        printf " %-7s |" "$ttime ms"
        ftime=$((ftime + ttime))
        times+=($ttime)
    done
    avg=$(bc -l <<< "scale=2; $ftime / $totaldomains")
    median=$(calculate_median "${times[@]}")

    printf " %-7.2f |\n" "$avg"
    
    results+=("$pname|$pip|$ftime|$avg|$median")
done

echo ""
echo "## Summary Table"
echo ""
echo "| DNS Name | DNS IP | Total Time | Average Time | Median Time |"
echo "|:---------|:-------|:-----------|:-------------|:------------|"

# Sort results by total time
IFS=$'\n' sorted_results=($(sort -t'|' -k3 -n <<<"${results[*]}"))

for result in "${sorted_results[@]}"; do
    IFS='|' read -r pname pip total avg median <<< "$result"
    printf "| %-8s | %-7s | %-11s | %-11s | %-10s |\n" "$pname" "$pip" "$total ms" "$avg ms" "$median ms"
done

exit 0;