I decided to share three small functions I made for IP addresses the other day in a few minutes.
Their use is as follows:

$isIPAddress(Possible IP address here)
example: $isIPAddress(1.2.3.4)
This returns whether the given text was an IP address.

$cmpIPAddress(Address one,Address two)
example: $cmpIPAddress(1.2.3.4,2.3.4.5)
This returns a comparison value for two IP addresses similar to strcmp() for string comparison in C.
-1 means the first is less than the second.
0 means they are equal.
1 means the first is greater than the second.

$isinIPRange(IP address range,IP address to check)
example: $isinIPRange(0.0.0.0-255.255.255.255,1.2.3.4)
This returns whether the IP address exists within the given range, in address1-address2 format.
The function will accept arguments where address2>address1.

I don't currently have a use for these, but perhaps you will or perhaps you can find something for me to improve on them.
Either way, enjoy. :)

; Returns whether a given IP address is valid
; example: $isIPAddress(1.2.3.4)
isIPAddress {
  tokenize 46 $1
  if ($1 isnum 0-255 && $2 isnum 0-255 && $3 isnum 0-255 && $4 isnum 0-255 && $5 == $null) return $true
  else return $false
}

; Returns a comparison value for the first IP address to the second (-1 less than, 0 equal, 1 greater than)
; example: $cmpIPAddress(1.2.3.4,2.3.4.5)
cmpIPAddress {
  if ($isIPAddress($1) && $isIPAddress($2)) {
    var %x 1, %result 0
    while (%x <= 4 && !%result) {
      if ($gettok($1,%x,46) < $gettok($2,%x,46)) %result = -1
      elseif ($v1 > $v2) %result = 1
      inc %x
    }
    return %result
  }
  else echo -s ERROR: $cmpIPAddress invalid parameters ( $+ $1- $+ )
}

; Returns whether a given IP address falls within the given range
; example: $isinIPRange(0.0.0.0-255.255.255.255,1.2.3.4)
isinIPRange {
  var %low $gettok($1,1,45), %high $gettok($1,2,45), %ip $2, %result $false
  if ($isIPAddress(%low) && $isIPAddress(%high) && $isIPAddress(%ip)) {
    ; Make sure low is actually the lowest (and vice versa)
    if ($cmpIPAddress(%low,%high) > 0) {
      var %temp = %low
      %low = %high
      %high = %temp
    }
    ; Compare
    if ($cmpIPAddress(%ip,%low) >= 0) {
      if ($cmpIPAddress(%ip,%high) <= 0) %result = $true
    }
  }
  else echo -s ERROR: $isinIPRange invalid parameters ( $+ $1- $+ )
  return %result
}