One, for long hand-authored regexen like this, try using the /x modifier. It would avoid the whitespace error and make your example easier to read as well.

my $ignore =
    qr( 192\.168\.188\.3 |
        192\.168\.11\.141 |
        192\.168\.140\.110 |
        192\.168\.186\.192 |
        192\.168\.186\.166 |
        192\.168\.139\.50 |
        192\.168\.139\.198 |
        192\.168\.132\.101 )x ;
[download]

Two, build your regexp from a data table. This gives the opportunity to use modules like Regex::PreSuf to optimize long lists. Think of all the time wasted in backtracking on the "192.168." part over and over.

use Regex::PreSuf;
my @ignore =
    qw( 192.168.188.3
        192.168.11.141
        192.168.140.110
        192.168.186.192
        192.168.186.166
        192.168.139.50
        192.168.139.198
        192.168.132.101 );
my $ignorex = presuf( map { s|\.|\\.|g } @ignore );
[download]

Lastly, now that the list of ignored IPs is really a list, it can come from a configuration file instead of from the script itself.

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