Hey, I am writing a little piece of code to check the sanity of an IP address. I haven't got it to break yet, so I was wondering if anyone else would have a go and see if there is anything wrong. Thanks!

#!/usr/bin/perl

use strict;

print "What IP address/Domain Name do you want to access: ";
$_ = <>;
my $ip = SanitizeIP($_);

print "$ip is sane.\n";
exit;



sub SanitizeIP {
    chomp ($_);
    my ($a,$c,$d,$e,$f);
    my $b = 0;
    if ($_ =~ /[a-zA-Z]+/) {
        print "$_\n";
        $_ = gethostbyname($_);
        ($c,$d,$e,$f) = unpack('C4', $_);
        $_ = $c . "." . $d . "." . $e . "." . $f;
    }

    my @_temp = split(/\./,$_);
    undef $_;
    
    foreach $a(@_temp) {
        if ($a =~ /\b\d\b|\b\d\d\b|\b\d\d\d\b/) {
            if (($a >= 0) and ($a <= 255)) {
                $_ = $_ . int($a);
                $_ = $_ . "." unless ($b > 2);
                $b++;
            }
            else {
                print "This is an illegal IP address -- or it sure see
+ms like one.\n";
                exit;
            }
        }
        else {
            print "This is an illegal IP address -- or it sure seems l
+ike one.\n";
            exit;
        }
    }
    
    if (($_ eq "") or ($_ eq " ")) {
        print "The Address did not resolve, or there was something wro
+ng with what you typed.\n";
        exit;
    }
    
    return $_;
}

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In reply to IP Address Sanity by Anonymous Monk

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