OUTER: foreach my $vhname (sort keys %vhosts) {
    for ($i = 0; $i <= $#{$vhosts{$vhname};}; ++$i) {
        if ($b eq $vhosts{$vhname}[$i]) {
            print "found '${b}'\n";
            last OUTER;
        }
    }
}

# perl foo
found 'l02duapofqa2_d1'