#/usr/bin/perl -w
use strict;
use CGI;
my $q = new CGI;

print $q->header();
# my $caller = $q->remote_host() so you know who called you
my $err = do_something()
print $err ? $err : "OK";

sub do_something { ... }

##</code><code>##

#!/usr/bin/perl -w 
use strict;
use LWP::Simple

while (1) {
    if ( some_event() ) {
        my $response = get('http://192.168.0.123/cgi-bin/server_b_script.pl');
        warn $response =~ m/OK/ ? "Notified server b OK\n" : "$response\n";
    }
    sleep 10;
}

# check for some event
sub some_event { ... }