a function to find the fastest free DNS server

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 ; }

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 ; }

Sample Output

$ timeDNS commandlinefu.com
192.168.0.1 ;; Query time: 2 msec
208.67.222.222 ;; Query time: 13 msec
198.153.192.1 ;; Query time: 17 msec
208.67.220.220 ;; Query time: 17 msec
156.154.71.1 ;; Query time: 18 msec
8.8.8.8 ;; Query time: 20 msec
156.154.70.1 ;; Query time: 22 msec
8.8.4.4 ;; Query time: 22 msec
198.153.194.1 ;; Query time: 27 msec

By: unixmonkey365

2011-08-18 01:11:53

dig echo grep sort function dig sponge

2 Alternatives + Submit Alt

a function to find the fastest free DNS server

Uses GNU Parallel. Show Sample Output
This is sample output - yours may be different.
```
208.67.222.222  ;; Query time: 18 msec
208.67.220.220  ;; Query time: 18 msec
198.153.194.1   ;; Query time: 22 msec
8.8.8.8 ;; Query time: 14 msec
8.8.4.4 ;; Query time: 18 msec
156.154.70.1    ;; Query time: 27 msec
198.153.192.1   ;; Query time: 42 msec
156.154.71.1    ;; Query time: 33 msec
```
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 31
a function to find the fastest DNS server

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. Show Sample Output
This is sample output - yours may be different.
```
12.876  200.187.95.4
```
1

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

glaudiston · 2017-02-02 12:00:38 20

What Others Think

This is odd. Today is the 22nd, and I posted it on the 18th, yet it's still not visible. WTF?

unixmonkey365 · 693 weeks ago

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KayGasaway · 146 weeks and 2 days ago

Took me time to read all the comments, but I really enjoyed the article. It proved to be Very helpful to me and I am sure to all the commenters here! It’s always nice when you can not only be informed, but also entertained! ???

KayGasaway · 145 weeks and 2 days ago

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Perfecthomepugs · 109 weeks and 1 day ago

pugpuppies95 · 71 weeks and 2 days ago

yeneba6574 · 24 weeks and 5 days ago

What do you think?

Any thoughts on this command? Does it work on your machine? Can you do the same thing with only 14 characters?

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