Question

35

How to check if a given ip falls between a given ip range using node js

rated 0 times [ 37] [ 2] / answers: 1 / hits: 16405 / 7 Years ago, wed, september 13, 2017, 12:00:00

Please pardon for this trival question

Given a set of Ip the set is quite large and might increase
https://github.com/client9/ipcat/blob/master/datacenters.csv#L4

Small example set - first column start ip second - end ip range

I will get the user ip from the request . I need to check if the ip falls in these set of ranges . How do i accomplish this.

I have looked into ip_range_check and range_check.

But they donot check for a ip given given range . How is thhis possible in node js with utmost performance. I dont want to go for a exhaustive search as performance is a hight priority.

Please help something new and quite challenging so far to me.

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marcelofrankiea

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3 Years ago

answered 7 Years ago aliah · Accepted Answer

This is quite easy if we convert the ips to simple numbers:

function IPtoNum(ip){

  return Number(

    ip.split(.)

      .map(d => (000+d).substr(-3) )

      .join()

  );

}

Then we can check a certain range as:

 if( IPtoNum(min) < IPtoNum(val) &&    IPtoNum(max) > IPtoNum(val) ) alert(in range);

That can also be applied to a table:

const ranges = [

  [..41, 192.168.45],

  [123.124.125, 126.124.123]

];



const ip = 125.12.125;

const inRange = ranges.some(

  ([min,max]) => IPtoNum(min) < IPtoNum(ip) &&   IPtoNum(max) > IPtoNum(ip)

);