IP to ISP/Country/City (GeoIP) using PHP

I've noted that many people are searching here about how to find out City/Country/ISP details from IP; often referred as GeoIP. Here, I've compiled my replies that once I posted to comp.lang.php

Get the IP

Refer http://www.iana.org/assignments/ipv4-address-space/ipv4-address-space.xml and see which whois server should be used for the whois lookup

Now, do the whois lookup. e.g., whois -h whois.apnic.net 61.x.x.x

Parse the results. AFAIK, it will have the ISP, City and Country info

For whois lookup, may use rwhois protocol through below PHP code:



<?php
function whois($host, $command)
{
  $fp = fsockopen ($host, 43, $errno, $errstr, 100);
  if (!$fp) {
     $result = $errstr . $errno . "\n";
  } else {
    fputs ($fp, $command . "\r\n\r\n");
    $result = '';
    while (!feof($fp)) {
      $result .= fgets ($fp, 128);
    }
    fclose ($fp);
  }
  return $result;
}

//debug...
echo whois('whois.internic.net', 'php.net');
?>

Comments

Photo got published in Kumudam magazine

I'm extremely surprised to find that the photo I took in Dakshina Chitra and later uploaded to Wikipedia got published in Kumudam magazine (dated July 1, 2009).

Hardening WordPress at WordPress Community Meetup - Mar 2020

Today spoke about hardening WordPress at the WordPress meetup . It's a nice experience as the audience were from mixed backgrounds (developing, marketing, product management, etc). My slides and links are available in the Pinboard . I have also shared an actionable checklist to harden a WordPress instance, that anyone can use in the form of the Restyaboard app (Restyaboard similar to Trello but open source and can self-host).

Interview question #2

This is related to PHP's array . An array has number of elements. All elements are integers and unique, which means there is no repetitive integers. (e.g.) $foo = array(7, 5, 9, 13, 2, 8); You have to sort the array, provided: You should scan the elements only once. You're not allowed to compare the elements when sorting. (i.e., you're not supposed to use any comparison operators) Sorted resultant array may not be the source array. How will you do that?