One way to do it is to generate a lookup hash keyed on your search data. Here's a starting point:

use warnings;
use strict;

my @file1 =
    (
    '1141286452,ServerA,Disk Full',
    '1141286737,ServerB,Net Down',
    '1141286737,ServerC,Disk Full'
    );
    
my @file2 =
    (
    '1141286737,ServerB,Net Down',
    '1141286780,ServerD,Bit Bucket Missing'
    );

my %file1LookUp;

push @{$file1LookUp{$file1[$_ - 1]}}, $_ for (1..@file1);

for (@file2) {
    print "Matched $_ at line(s) @{$file1LookUp{$_}}\n" if exists $fil
+e1LookUp{$_};
}
[download]

Prints:

Matched 1141286737,ServerB,Net Down at line(s) 2
[download]