diff --git a/pandora_server/lib/PandoraFMS/Recon/Base.pm b/pandora_server/lib/PandoraFMS/Recon/Base.pm
index 81e7d5993f..7966e97de0 100644
--- a/pandora_server/lib/PandoraFMS/Recon/Base.pm
+++ b/pandora_server/lib/PandoraFMS/Recon/Base.pm
@@ -1421,6 +1421,8 @@ sub scan_subnet($) {
     # By default 200, (20 * 10)
     my $host_block_size = $self->{'block_size'};
 
+    $host_block_size = 50 unless defined($self->{'block_size'});
+
     # The first 50% of the recon task approx.
     my $step = 25.0 / scalar(@subnets) / (($total_hosts / $host_block_size)+1);
     my $subnet_step = 50.0 / (($total_hosts / $host_block_size)+1);
diff --git a/pandora_server/lib/PandoraFMS/Tools.pm b/pandora_server/lib/PandoraFMS/Tools.pm
index 92c6a06cd5..76aaefc344 100755
--- a/pandora_server/lib/PandoraFMS/Tools.pm
+++ b/pandora_server/lib/PandoraFMS/Tools.pm
@@ -1453,6 +1453,8 @@ sub pandora_block_ping($@) {
 	my ($pa_config, @hosts) = @_;
 	my ($cmd, $output);
 
+	return () if is_empty(@hosts);
+
 	if (-x $pa_config->{'fping'}) {
 		# fping timeout in milliseconds
 		$cmd = $pa_config->{'fping'} . " -a -q -t " . (1000 * $pa_config->{'networktimeout'}) . " " . (join (' ', @hosts));