This may be what you want now, but really you need to sort out what problem you actually need to solve.

Note that this is still reading the data a line at a time rather than slurping the data as your code was. Unless this code is part of something larger that needs to further process the original data there is no advantage in slurping everything. Even if you did need to process the data further, you would be better to slurp into an array than to slurp the whole thing into a scalar.

use strict;
use warnings;

my $dumpIPs = 0;

while (<DATA>) {
  if ($dumpIPs and /((\d{1,3}\.){3}\d{1,3})/) {
    print "$1 ";
  } elsif ($dumpIPs) {
    print "\n\n";
    $dumpIPs = 0;
  }

  if (/\b(?:Device|interface|VRID|state|primary address)\b/i) {
    print;
    $dumpIPs = 0;
  }
  
  $dumpIPs ||= /Number addresses/;
}
[download]

Prints:

 logging to Device F01 is 19.9.16.11...
Interface WEB_A
    VRID 39
        State:        Master        Time since transition:    
                Primary address:    195.51.205.220
195.51.205.222 

Interface DATA_DL
    VRID 2556
        State:        Master        Time since transition:    
        Primary address:    19.18.27.65
15.12.57.234 

 logging to Device L2 is 14.359.1.2...
Interface SDC_A
    VRID 9
        State:        Backup        Time since transition:    
        Primary address:    195.51.205.221
195.51.205.222 

Interface SA
    VRID 7
        State:        Backup        Time since transition:    
        Primary address:    62.187.224.13
6.17.26.14
[download]

#usr/bin/perl

use Spreadsheet::WriteExcel;

my $workbook = Spreadsheet::WriteExcel->new("vrrp.xls");
my $worksheet = $workbook->add_worksheet();

$worksheet->write ("A1", 'Device');
$worksheet->write ("B1", 'Interface Name');
$worksheet->write ("C1", 'VRID');
$worksheet->write ("D1", 'State');
$worksheet->write ("E1", 'Primary ip address');
$worksheet->write ("F1", 'VRRP Address');

my $row = 2;
my $line = '';
my $device;

open inFile, '<', 'svrrp.txt' or die "Couldn't open svrrp.txt: $!";

while (! eof inFile)
  {
      $line .= ' ' . <inFile>;
          chomp $line;
          
        next if ! ($line =~ /logging\sto\sDevice\s(.*?)\s+/i) and ! eo
+f inFile;
        my $nextDevice = $1;  
        next if ! ($line =~ /Interface\s(.*?)\s+/i)  ;
        my $nextInterface = $1;
        
                
                #next if ! ($line =~ /Interface\s(.*?)\s+/i)  ;
                              #my $nextInterface = $1;
                    {            
                        if ($line=~ m[
                            (?=.*? nterface           \s+ (\S+) )
                                      (?=.*? VRID               \s+ (\
+S+) )
                                    (?=.*? State:             \s+ (\S+
+) )
                                  (?=.*? Primary\saddress:  \s+ (\S+) 
+)]smx)
                         {
                            $worksheet->write("A$row", "$device");
                            $worksheet->write("B$row", "$1");
                            $worksheet->write("C$row", "$2");
                            $worksheet->write("D$row", "$3");
                            $worksheet->write("E$row", "$4");
        
                            my (@ip)=($line=~m/number addresses(?:.*?)
+((?:\d{1,3}\.){3}\d{1,3})/gsi);
                            print "The addresses are: ". join("\n",@ip
+)."\n\n";
    
                            print " end\n\n";
                             $worksheet->write("F$row", join("\n",@ip)
+);
                            
                 ++$row;
                        }
                              else          { print "no match found\n"
+ ; }
                  
                        print "$device,$Interface,$1, $2, $3, $4 \n";
                    }                
                
             $Interface = $nextInterface;
                        
         ++$row;    
 $device = $nextDevice;
    
$line = " ";
}

close inFile;
$workbook->close();
[download]

can you figure out what is the problem in this ?