最近CloudFlare推出了自己的免费DNS解析器：1.1.1.1，可以说CloudFlare是我比较喜欢的一个公司之一，当时在想具体性能怎么样，所以找了个工具本地测试了下。
Shell脚本测试公共dns的性能，可以测试各个dns server的解析速度，标准输出如下：
{ dnsperftest } master » bash ./dnstest.sh |sort -k 22 -n
test1 test2 test3 test4 test5 test6 test7 test8 test9 test10 Average
norton 32 ms 32 ms 32 ms 32 ms 29 ms 31 ms 31 ms 31 ms 37 ms 33 ms 32.00
google 7 ms 50 ms 6 ms 4 ms 62 ms 225 ms 6 ms 48 ms 5 ms 48 ms 46.10
opendns 6 ms 73 ms 4 ms 4 ms 71 ms 342 ms 5 ms 74 ms 5 ms 73 ms 65.70
neustar 28 ms 117 ms 28 ms 26 ms 112 ms 117 ms 26 ms 116 ms 28 ms 113 ms 71.10
quad9 27 ms 199 ms 24 ms 25 ms 182 ms 191 ms 26 ms 185 ms 24 ms 191 ms 107.40
cleanbrowsing 4 ms 217 ms 5 ms 5 ms 219 ms 219 ms 4 ms 219 ms 4 ms 219 ms 111.50
cloudflare 4 ms 234 ms 4 ms 4 ms 226 ms 226 ms 3 ms 258 ms 3 ms 232 ms 119.40
yandex 5 ms 212 ms 4 ms 5 ms 265 ms 251 ms 4 ms 205 ms 5 ms 241 ms 119.70
adguard 7 ms 258 ms 7 ms 6 ms 233 ms 242 ms 7 ms 234 ms 5 ms 257 ms 125.60
comodo 4 ms 281 ms 4 ms 4 ms 326 ms 327 ms 6 ms 325 ms 6 ms 324 ms 160.70具体脚本：
#!/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; }
NAMESERVERS=`cat /etc/resolv.conf | grep ^nameserver | cut -d " " -f 2 | sed 's/\(.*\)/&#&/'`
PROVIDERS="
1.1.1.1#cloudflare
4.2.2.1#level3
8.8.8.8#google
9.9.9.9#quad9
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
176.103.130.132#adguard
156.154.70.3#neustar
8.26.56.26#comodo
"
# Domains to test. Duplicated domains are ok
DOMAINS2TEST="www.google.com amazon.com facebook.com www.youtube.com www.reddit.com wikipedia.org twitter.com gmail.com www.google.com whatsapp.com"
totaldomains=0
printf "%-18s" ""
for d in $DOMAINS2TEST; do
totaldomains=$((totaldomains + 1))
printf "%-8s" "test$totaldomains"
done
printf "%-8s" "Average"
echo ""
for p in $NAMESERVERS $PROVIDERS; do
pip=${p%%#*}
pname=${p##*#}
ftime=0
printf "%-18s" "$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$ttime" = "x0" ]; then
ttime=1
fi
printf "%-8s" "$ttime ms"
ftime=$((ftime + ttime))
done
avg=`bc -lq <<< "scale=2; $ftime/$totaldomains"`
echo " $avg"
done
exit 0;