I think this what you are looking for: 
use strict;
use warnings;

my %HoA;
while ( <DATA> ) {
       my @array_ip;
       chomp;
       my ($swit,$server,$ip_range) = split;

       my ($b_real_ip,$b_ip, $temp, $e_ip) = $ip_range =~ m#(\d+\.\d+\
+.\d+\.)(\d+)\-(\d+\.\d+\.\d+\.)(\d+)#;
       my $b_ip_copy = $b_ip;
       my @ip_g;
       while ( $b_ip_copy <= $e_ip) {
           my $b_ip_final = join('',$b_real_ip,$b_ip_copy);
           push @ip_g , $b_ip_final;
           ++$b_ip_copy;
       }
       $HoA{ join('_',$swit,$server,$b_real_ip) } = \@ip_g;
}

for my $key (sort keys %HoA)
{
    
    for my $key2 (@{  $HoA{ $key }  })
    {
        print "$key\t";    
        print "$key2\n";
    }
    print "\n";
}
__DATA__
server    1    10.1.1.1-10.1.1.5
server    2    192.168.1.1-192.168.1.5
server    1    192.168.1.1-192.168.1.2

[download]

In reply to Re: assigning hash key to reference of array question by umasuresh
in thread assigning hash key to reference of array question by Anonymous Monk

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.