验证IPv4 IP地址是否有效

Posted 2021-02-27

This code will validate not only the four octets contain between 1 and 3 numbers each, but also that the number they contain is between 0 and 255.

In all, there are 3 different regex's that I tried and all seem to work fine. The three regex's are:

1. m/^(dd?d?).(dd?d?).(dd?d?).(dd?d?)/
2. m/dd?d?.dd?d?.dd?d?.dd?d?/
3. m/d{1,2}.d{1,3}.d{1,3}.d{1,3}/

The first one is used below. Enjoy!!!

#!/usr/bin/perl
 
use strict;
use warnings;
 
 
print("What is the IP Address you would like to validate: ");
my $ipaddr = <STDIN>;
chomp($ipaddr);
 
 
if( $ipaddr =~ m/^(dd?d?).(dd?d?).(dd?d?).(dd?d?)$/ )
{
    print("IP Address $ipaddr  -->  VALID FORMAT! 
");
 
    if($1 <= 255 && $2 <= 255 && $3 <= 255 && $4 <= 255)
    {
        print("IP address:  $1.$2.$3.$4  -->  All octets within range
");
    }
    else
    {
        print("One of the octets is out of range.  All octets must contain a number between 0 and 255 
");
    }
}
else
{
    print("IP Address $ipaddr  -->  NOT IN VALID FORMAT! 
");
}