[SOLVED] Verify IP address is valid.

[lynxus]

Hi guys, Im trying to figure out how to verify a IP address is valid but failing lol. Mainly because im new to PHP.

 

So any help would be oh so helpfull!

 

My script normally contains quite a lot of  IP address's so what would be handy is if one of my vars had a invalid IP it would make my global var of $error = "1" and maybe echo what $var had the bad ip in.

 

So in this instance i would have something like..

 

$ip1 = _$POST['$ip1'];

$ip2 = _$POST['$ip2'];

$ip3 = _$POST['$ip3'];

 

lets say ip1 had "10.0.0.0" that would be valid ( 4 octets full and below 256 )

if it had "10.0.0"  that would be invalid. not 4 octects

if it had "10.0.0.300" that would be invalid.. 4 octect but over 255 ..

 

Does this make any sense?

 

How would i go about validating these vars and then changing my global $error var to 1 if they fail the check?

 

I suppose a function?

 

function checkip($ip){

if $ip = invalid then return "1";

}

 

$error = checkip($ip1);

 

Im guess i sorta see what i need to do? but reallly need help on actually doing it?

 

Many Thanks

Graham

 

[GingerRobot]

Well, the function would probably look something like:

 

<?php
function verify_ip($ip){
    $parts = explode('.',$ip);
    if(count($parts) < 4){
        return FALSE;
    }
    foreach($parts as $v){
        if(!ctype_digit($parts) || $parts > 255){
            return FALSE;
        }
    }
    return TRUE;
}
?>

[rhodesa]

I would shorten it up with regex and do a lookup:

 

<?php
function verify_ip($ip){
  if(preg_match('/^(\d{1,3}\.){3}\d{1,3}$/',$ip)) //Make sure it's ###.###.###.###
    return checkdnsrr($ip); //Check DNS
  return false;
}
?>

[lynxus]

I would shorten it up with regex and do a lookup:

 

<?php
function verify_ip($ip){
  if(preg_match('/^(\d{1,3}\.){3}\d{1,3}$/',$ip)) //Make sure it's ###.###.###.###
    return checkdnsrr($ip); //Check DNS
  return false;
}
?>

 

Hi thanks ( both of you )

I will give them a try and see what happens Thanks

-g