use strict;
use warnings;

my ( $file, $loop, %seen ) = 'junk.txt';

open my $fh1, '<', $file or die "Unable to open $file: $!";
while ( my $fileName = <$fh1> ) {
    chomp $fileName;

    print "The packet traversed this path in $fileName:\n";

    open my $fh2, '<', $fileName or die "Unable to open $fileName: $!";
    while ( my $fileLine = <$fh2> ) {
        $fileLine =~ /(\d+\.\d+\.\d+\.\d+)/ or next;
        $loop++ if ++$seen{$1} > 1;
        print "$1\n";
    }

    close $fh2;
    print "\n";
}

close $fh1;

print "** Routing Loop Detected **\n" if $loop;