Test DNS resolution time

test_dns.sh

#!/bin/bash

# List of top 100 domains
domains=(
    "google.com"
    "youtube.com"
    "facebook.com"
    "baidu.com"
    "wikipedia.org"
    "yahoo.com"
    "reddit.com"
    "google.co.in"
    "qq.com"
    "taobao.com"
    "amazon.com"
    "tmall.com"
    "twitter.com"
    "sohu.com"
    "instagram.com"
    "vk.com"
    "jd.com"
    "sina.com.cn"
    "weibo.com"
    "live.com"
    "360.cn"
    "yandex.ru"
    "blogspot.com"
    "netflix.com"
    "linkedin.com"
    "twitch.tv"
    "pages.tmall.com"
    "mail.ru"
    "microsoft.com"
    "aliexpress.com"
    "pinterest.com"
    "google.co.jp"
    "xvideos.com"
    "google.de"
    "office.com"
    "google.co.uk"
    "bing.com"
    "google.fr"
    "google.com.br"
    "google.ru"
    "google.it"
    "google.es"
    "google.ca"
    "google.com.hk"
    "ebay.com"
    "msn.com"
    "pornhub.com"
    "google.com.mx"
    "whatsapp.com"
    "yahoo.co.jp"
    "google.co.kr"
    "google.com.tr"
    "google.com.au"
    "xhamster.com"
    "imgur.com"
    "google.com.ar"
    "google.pl"
    "google.co.th"
    "google.nl"
    "google.com.sa"
    "google.co.id"
    "google.com.eg"
    "google.ae"
    "google.com.sg"
    "google.com.ua"
    "google.co.za"
    "naver.com"
    "babytree.com"
    "alipay.com"
    "microsoftonline.com"
    "hao123.com"
    "wikia.com"
    "myshopify.com"
    "quora.com"
    "tumblr.com"
    "google.gr"
    "google.com.ph"
    "google.ro"
    "google.cl"
    "google.se"
    "google.pt"
    "google.com.ng"
    "google.ch"
    "google.be"
    "google.com.my"
    "google.cz"
    "google.co.ve"
    "google.hu"
    "ok.ru"
    "m.baidu.com"
    "soso.com"
    "google.at"
    "google.dz"
    "google.com.pk"
    "google.ie"
    "google.co.nz"
    "google.com.vn"
    "google.sk"
    "google.co"
    "google.no"
)

# Output file to record results
OUTPUT_FILE="dns_query_results.log"
# Temporary file to store response times
TEMP_FILE=$(mktemp)

# Initialize output file
echo "DNS Query Results" > $OUTPUT_FILE
echo "Timestamp, Domain, Response Time (ms)" >> $OUTPUT_FILE

# Function to perform a DNS query
perform_query() {
  local domain=$1
  local start_time=$(date +%s%3N)
  local response_time=$(dig +tcp +stats $domain | grep "Query time:" | awk '{print $4}')
  local end_time=$(date +%s%3N)

  # If response_time is empty, it means dig failed, set a large response time
  if [[ -z "$response_time" ]]; then
    response_time=9999
  fi

  local timestamp=$(date +'%Y-%m-%d %H:%M:%S')
  echo "$timestamp, $domain, $response_time" >> $OUTPUT_FILE

  if (( response_time > 300 )); then
    echo "$timestamp, $domain, $response_time" >> dns_queries_over_300ms.log
  fi

  echo "$response_time" >> $TEMP_FILE
}

# Start the time limit
end_time=$((SECONDS + 300))

# Perform queries for 5 minutes
while [[ $SECONDS -lt $end_time ]]; do
  # Get a random domain from the array
  domain=${domains[RANDOM % ${#domains[@]}]}
  perform_query $domain
  sleep 1
done

# Calculate mean response time
total_response_time=$(awk '{ sum += $1 } END { print sum }' $TEMP_FILE)
num_queries=$(wc -l < $TEMP_FILE)
mean_response_time=$(echo "scale=2; $total_response_time / $num_queries" | bc)

# Output mean response time
echo "Mean Response Time: $mean_response_time ms" >> $OUTPUT_FILE

# Clean up temporary file
rm $TEMP_FILE

echo "DNS querying complete. Results are in $OUTPUT_FILE and dns_queries_over_300ms.log."