function IsValidIP(
    const S: String
): Boolean;

Boolean - True when a dotted-decimal IP address is detected.

IsValidIP is a Boolean function that indicates if the S argument contains a valid IP address in dotted-decimal form. IsValidIP returns True when the string contains 4 decimal segments, each having a value in the range 0 to 255. For example: 

• "127.0.0.1" returns True.
• "127.256.0.1" returns False.