a function to find the fastest DNS server

curl -s http://public-dns.info/nameserver/br.csv| cut -d, -f1 | xargs -i timeout 1 ping -c1 -w 1 {} | grep time | sed -u "s/.* from \([^:]*\).*time=\([^ ]*\).*/\2\t\1/g" | sort -n | head -n1
http://public-dns.info gives a list of online dns servers. you need to change the country in url (br in this url) with your country code. this command need some time to ping all IP in list.
Sample Output
12.876  200.187.95.4

1
2017-02-02 12:00:38

2 Alternatives + Submit Alt

  • Uses GNU Parallel. Show Sample Output


    8
    timeDNS() { parallel -j0 --tag dig @{} "$*" ::: 208.67.222.222 208.67.220.220 198.153.192.1 198.153.194.1 156.154.70.1 156.154.71.1 8.8.8.8 8.8.4.4 | grep Query | sort -nk5; }
    unixmonkey74668 · 2015-04-26 08:22:32 1
  • Evoke from the command like as: timeDNS commandlinefu.com . This isn't too terribly practical, but it is a good code example of using subshells to run the queries in parallel and the use of an "anonymous function" (a/k/a "inline group") to group i/o. . I'm assuming you have already defined your local DNS cache as ${local_DNS}, (here, it's 192.168.0.1). . You do need to install `moreutils` to get `sponge`. . If you're willing to wait, a slower version w/o sponge, (and w/o sorting), is this: . DNS () { for x in "192.168.0.1" "208.67.222.222" "208.67.220.220" "198.153.192.1" "198.153.194.1" "156.154.70.1" "156.154.71.1" "8.8.8.8" "8.8.4.4"; do (echo -n "$x "; dig @"$x" "$*"|grep Query) ; done ; } Show Sample Output


    1
    timeDNS () { { for x in "${local_DNS}" "208.67.222.222" "208.67.220.220" "198.153.192.1" "198.153.194.1" "156.154.70.1" "156.154.71.1" "8.8.8.8" "8.8.4.4"; do ({ echo -n "$x "; dig @"$x" "$*"|grep Query ; }|sponge &) done ; } | sort -n -k5 ; }
    unixmonkey365 · 2011-08-18 01:11:53 1

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