Validating special form of IP address - php

Question

I have encountered a strange IP which has redundant zero values among the octets. Is there anyway to properly validate this as an IP or use regular expression to remove those redundant zeroes?
example is of follows:
218.064.215.239 (take note of the extra zero at the second octet "064").
I do have one working IP validation function but it will not validiate this Ip properly due to the nature of the regular expression unable to accept that extra zero. Following is the code in PHP:
function valid_ip($ip) {
return preg_match("/^([1-9]|[1-9][0-9]|1[0-9][0-9]|2[0-4][0-9]|25[0-5])" .
"(\.([0-9]|[1-9][0-9]|1[0-9][0-9]|2[0-4][0-9]|25[0-5])){3}$/", $ip);
}
thanks for any help in advance peeps! :D

Answer 1

This will correct them:
$ip = "123.456.007.89";
$octets = explode(".", $ip);
$corrected = array();
foreach ($octets as $octet) {
array_push($corrected, (int)$octet);
}
echo implode(".", $corrected);

Answer 2

You have to accept the zero like this:
^(0?[1-9]|0?[1-9][0-9]|1[0-9][0-9]|2[0-4][0-9]|25[0-5])(\.(0?[0-9]|0?[1-9][0-9]|1[0-9][0-9]|2[0-4][0-9]|25[0-5])){3}$
Play with this regular expression on rubular.com.
The 0? I added matches zero or one occurence of 0. So 0?[1-9][0-9] for example matches both 010 and 10 for example.

Answer 3

Change the bare |1 occurrences to |[01]. Are you sure this is not supposed to be interpreted as an octal number, though? Some resolvers do that.

Answer 4

Use ip2long().

Answer 5

You should figure out where those extra zeroes are coming from. Those leading zeroes can't be just dropped. On most platforms they mean that the octet is in octal form instead of decimal. That is: 064 octal equals 52 decimal.

Answer 6

Did you have a go yourself? It's really quite simple.
|1[0-9][0-9]| matches 100-199, as you are now wanting to match 000-199 (as above that it is 200-155) you just need to make a set for the 1 to be 1 or 0.
function valid_ip($ip) {
return preg_match("/^([1-9]|[1-9][0-9]|[01][0-9][0-9]|2[0-4][0-9]|25[0-5])".
"(\.([0-9]|[1-9][0-9]|[01][0-9][0-9]|2[0-4][0-9]|25[0-5])){3}$/", $ip);
}
And that can be refactored down (allowing leading zeroes) to:
function valid_ip($ip) {
return preg_match("/^([01]?[0-9]{1,2}|2[0-4][0-9]|25[0-5])".
"(\.([01]?[0-9]{1,2}|2[0-4][0-9]|25[0-5])){3}$/", $ip);
}
Or to strip these unneeded zeros:
function strip_ip($ip) {
return preg_replace( '/0+([^0])(\.|$)/' , '$1$2' , $ip );
}