Thanks. This is what I came up with based on your code:

use warnings;
use strict;

my @ips = qw/192.168.2.1 ..../;

@ips = map { quotemeta } @ips;
 
my $regex = join('|', @ips);
my $re = qr[$regex];

while (<>) {
    print if /$re/;
}
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I'm then calling it liks so:

tail -f fw.log | /usr/local/scripts/parseips
[download]

It's taking up quite a bit of resources, but not bringing the server to it's knees.

Thank you for the other suggestions also. I'm going to come up with a more perm. solution based on one of these that does not require me to stare at a terminal.