Validate IPv4 Address in PHP

Today I am going to tell how to validate IPv4 / IP address using PHP. Simple function which will used to check client IP address is valid or not.

Steps to validate IPv4 Address in PHP

• Split IP address into segments  by dot(.)  using explode function
• Make sure that there are 4 segments (eg : 192.168.1.45)
• Make sure that IP cannot start with 0
• IP segments must be digits & cannot be longer than 3 digits or greater than 255

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For Demo Click Here

Getting country , city name from IP address in PHP

I’ve used the API from hostip.info to fetch the country name , city name and country code from the given IP address. I’ve mad this function in PHP which uses XML response from hostip.info and extracted country name, city name and country code using regular expression.

Function to return country, city name from IP address in PHP

function countryCityFromIP($ipAddr)

{

//function to find country and city from IP address

//Developed by Roshan Bhattarai http://roshanbh.com.np

//verify the IP address for the

ip2long($ipAddr)== -1 || ip2long($ipAddr) === false ? trigger_error("Invalid IP", E_USER_ERROR) : "";

$ipDetail=array(); //initialize a blank array

//get the XML result from hostip.info

$xml = file_get_contents("http://api.hostip.info/?ip=".$ipAddr);

//get the city name inside the node <gml:name> and </gml:name>

preg_match("@<Hostip>(\s)*<gml:name>(.*?)</gml:name>@si",$xml,$match);

//assing the city name to the array

$ipDetail['city']=$match[2]; 

//get the country name inside the node <countryName> and </countryName>

preg_match("@<countryName>(.*?)</countryName>@si",$xml,$matches);

//assign the country name to the $ipDetail array

$ipDetail['country']=$matches[1];

//get the country name inside the node <countryName> and </countryName>

preg_match("@<countryAbbrev>(.*?)</countryAbbrev>@si",$xml,$cc_match);

$ipDetail['country_code']=$cc_match[1]; //assing the country code to array

//return the array containing city, country and country code

return $ipDetail;

}

Download Source Code

As you can see, I’ve documented all the PHP code and I don’t think I need explain anymore about that code. Just notice that, this function returns the array containg three key elements “country” , “city” and “country_code”. Each elements have the value of city, country and country code.

Now, look the the how we can use the above function in PHP,

$IPDetail=countryCityFromIP('12.215.42.19');

echo $IPDetail['country']; //country of that IP address

echo $IPDetail['city']; //outputs the IP detail of the city

Notice that the above PHP function returns the array containing the country , city and country code from IP Address and we can use them in PHP. If you want to know how to get IP address in PHP, you can check this post how you can get real IP address in PHP.

Ip address validation in PHP using regular expression

If you don’t know how to validate the IP address format in PHP, then you are in the right place.I’ll show you here how to validate the IP address using regular expression in PHP.

As you guyz know, IP address consists four parts. Each parts separated by period “.” and these part consists the digits which ranges from 0 to 255.

Function to validate IP address in PHP using Regular Expression

//function to validate ip address format in php by Roshan Bhattarai(http://roshanbh.com.np)

function validateIpAddress($ip_addr)

{

  //first of all the format of the ip address is matched

  if(preg_match("/^(\d{1,3})\.(\d{1,3})\.(\d{1,3})\.(\d{1,3})$/",$ip_addr))

  {

    //now all the intger values are separated

    $parts=explode(".",$ip_addr);

    //now we need to check each part can range from 0-255

    foreach($parts as $ip_parts)

    {

      if(intval($ip_parts)>255 || intval($ip_parts)<0)

      return false; //if number is not within range of 0-255

    }

    return true;

  }

  else

    return false; //if format of ip address doesn't matches

}

As you can see above, first of all the format of the “$ip_addr” is validated using regular expression. In the regular expression “\d{1,3}” means that there should be digits which can be either 1 to 3 digits because a IP Adress can be “222.0.123.12″ or 

“12.15.123.5″. So, each part can consists 1 to 3 digits.

After validating the format using regular expression, each part of the IP address is separated using period(“.”) using explode() function available in PHP. And finally, it is checked that each part of the IP address is between 0 to 225 or not.

Getting real IP address in PHP

Are you using $_SERVER['REMOTE_ADDR'] to find the the client’s IP address in PHP? Well dude, you might be amazed to know that it may not return the true IP address of the client at all time. If your client is connected to the Internet through Proxy Server then $_SERVER['REMOTE_ADDR'] in PHP just returns the the IP address of the proxy server not of the client’s machine. 

So here is a simple function in PHP to find the real IP address of the client’s machine. There are extra Server variable which might be available to determine the exact IP address of the client’s machine in PHP, they are HTTP_CLIENT_IP and HTTP_X_FORWARDED_FOR.

Function to find real IP address in PHP:

function getRealIpAddr()
{ 
  if (!empty($_SERVER['HTTP_CLIENT_IP']))   //check ip from share internet  
      {       $ip=$_SERVER['HTTP_CLIENT_IP'];     } 
]))   //to check ip is pass from proxy     {       $ip=$_SERVER['HTTP_X_FORWARDED_FOR'];
    elseif (!empty($_SERVER['HTTP_X_FORWARDED_FOR '     }     else     {       $ip=$_SERVER['REMOTE_ADDR'];     }     return $ip; 
 
}

In this PHP function, first attempt is to get the direct IP address of client’s machine, if not available then try for forwarded for IP address using HTTP_X_FORWARDED_FOR. And if this is also not available, then finally get the IP address using REMOTE_ADDR.