diff --git a/install/dist/lib/centos_base.lib.php b/install/dist/lib/centos_base.lib.php
index 4f078b2951a2c2eca1d534bb593de290992a3399..15074d474a6c4fffd3dc9388fa4f1b228b364e8e 100644
--- a/install/dist/lib/centos_base.lib.php
+++ b/install/dist/lib/centos_base.lib.php
@@ -71,13 +71,13 @@ class installer_centos extends installer_dist {
 
 		// Adding amavis-services to the master.cf file if the service does not already exists
 		if ($this->postfix_master()) {
-			exec ("postconf -M amavis.unix", $out, $ret);
+			exec ("postconf -M amavis.unix &> /dev/null", $out, $ret);
 			$add_amavis = @($out[0]=='')?true:false;
 			unset($out);
-			exec ("postconf -M 127.0.0.1:10025.inet", $out, $ret);
+			exec ("postconf -M 127.0.0.1:10025.inet &> /dev/null", $out, $ret);
 			$add_amavis_10025 = @($out[0]=='')?true:false;
 			unset($out);
-			exec ("postconf -M 127.0.0.1:10027.inet", $out, $ret);
+			exec ("postconf -M 127.0.0.1:10027.inet &> /dev/null", $out, $ret);
 			$add_amavis_10027 = @($out[0]=='')?true:false;
 			unset($out);
 		} else { //* fallback - postfix < 2.9
diff --git a/install/dist/lib/debian60.lib.php b/install/dist/lib/debian60.lib.php
index a53c603d4385e9b2cd563ae4cadae397543adb63..b5495fa35300ea6a9caa579d5cb4442a833943a5 100644
--- a/install/dist/lib/debian60.lib.php
+++ b/install/dist/lib/debian60.lib.php
@@ -53,7 +53,7 @@ class installer extends installer_base {
 		$config_dir = $conf['postfix']['config_dir'];
 		//* Configure master.cf and add a line for deliver
 		if ($this->postfix_master()) {
-			exec ("postconf -M dovecot.unix", $out, $ret);
+			exec ("postconf -M dovecot.unix &> /dev/null", $out, $ret);
  			$add_dovecot_service = @($out[0]=='')?true:false;
 		} else { //* fallback - postfix < 2.9
 			$content = rf($config_dir.'/master.cf');
diff --git a/install/dist/lib/fedora.lib.php b/install/dist/lib/fedora.lib.php
index f0630294e0529ba0156915e8351692bf2e4e77e6..b8ce46a3726e660bc97bdd2e4005ae9ec5162468 100644
--- a/install/dist/lib/fedora.lib.php
+++ b/install/dist/lib/fedora.lib.php
@@ -352,7 +352,7 @@ class installer_dist extends installer_base {
 		$config_dir = $conf['postfix']['config_dir'];
 		//* Configure master.cf and add a line for deliver
 		if ($this->postfix_master()) {
-			exec ("postconf -M dovecot.unix", $out, $ret);
+			exec ("postconf -M dovecot.unix &> /dev/null", $out, $ret);
 			$add_dovecot_service = @($out[0]=='')?true:false;
 		} else { //* fallback - postfix < 2.9
 			$content = rf($config_dir.'/master.cf');
@@ -493,13 +493,13 @@ class installer_dist extends installer_base {
 
 		// Adding amavis-services to the master.cf file if the service does not already exists
 		if ($this->postfix_master()) {
-			exec ("postconf -M amavis.unix", $out, $ret);
+			exec ("postconf -M amavis.unix &> /dev/null", $out, $ret);
 			$add_amavis = @($out[0]=='')?true:false;
 			unset($out);
-			exec ("postconf -M 127.0.0.1:10025.inet", $out, $ret);
+			exec ("postconf -M 127.0.0.1:10025.inet &> /dev/null", $out, $ret);
 			$add_amavis_10025 = @($out[0]=='')?true:false;
 			unset($out);
-			exec ("postconf -M 127.0.0.1:10027.inet", $out, $ret);
+			exec ("postconf -M 127.0.0.1:10027.inet &> /dev/null", $out, $ret);
 			$add_amavis_10027 = @($out[0]=='')?true:false;
 			unset($out);
 		} else { //* fallback - postfix < 2.9
diff --git a/install/dist/lib/gentoo.lib.php b/install/dist/lib/gentoo.lib.php
index 718681bbc1822a73e965cfd2005ec379bdd05ff9..e15368bf5e47e050e880388c853cf6ccd915a980 100644
--- a/install/dist/lib/gentoo.lib.php
+++ b/install/dist/lib/gentoo.lib.php
@@ -273,7 +273,7 @@ class installer extends installer_base
 		$config_dir = $conf['postfix']['config_dir'];
 		//* Configure master.cf and add a line for deliver
 		if ($this->postfix_master()) {
-			exec ("postconf -M dovecot.unix", $out, $ret);
+			exec ("postconf -M dovecot.unix &> /dev/null", $out, $ret);
 			$add_dovecot_service = @($out[0]=='')?true:false;
 		} else { //* fallback - postfix < 2.9
 			$content = rf($config_dir.'/master.cf');
@@ -395,13 +395,13 @@ class installer extends installer_base
 
 		// Adding amavis-services to the master.cf file if the service does not already exists
 		if ($this->postfix_master()) {
-			exec ("postconf -M amavis.unix", $out, $ret);
+			exec ("postconf -M amavis.unix &> /dev/null", $out, $ret);
 			$add_amavis = @($out[0]=='')?true:false;
 			unset($out);
-			exec ("postconf -M 127.0.0.1:10025.inet", $out, $ret);
+			exec ("postconf -M 127.0.0.1:10025.inet &> /dev/null", $out, $ret);
 			$add_amavis_10025 = @($out[0]=='')?true:false;
 			unset($out);
-			exec ("postconf -M 127.0.0.1:10027.inet", $out, $ret);
+			exec ("postconf -M 127.0.0.1:10027.inet &> /dev/null", $out, $ret);
 			$add_amavis_10027 = @($out[0]=='')?true:false;
 			unset($out);
 		} else { //* fallback - postfix < 2.9
diff --git a/install/dist/lib/opensuse.lib.php b/install/dist/lib/opensuse.lib.php
index 6f65ea92202219f32638d35f8b2844310ba3c5f3..60e3858bba3018d5c357559210a89721b2005342 100644
--- a/install/dist/lib/opensuse.lib.php
+++ b/install/dist/lib/opensuse.lib.php
@@ -229,7 +229,7 @@ class installer_dist extends installer_base {
 		$regex = "/^maildrop   unix.*pipe flags=DRhu user=vmail argv=\\/usr\\/bin\\/maildrop -d ".$cf['vmail_username']." \\$\{extension} \\$\{recipient} \\$\{user} \\$\{nexthop} \\$\{sender}/";
 		$configfile = $config_dir.'/master.cf';
 		if ($this->postfix_master()) {
-			exec ("postconf -M maildrop.unix", $out, $ret);
+			exec ("postconf -M maildrop.unix &> /dev/null", $out, $ret);
 			$change_maildrop_flags = @(preg_match($regex, $out[0]) && $out[0] !='')?false:true;
 		} else { //* fallback - postfix < 2.9
 			$change_maildrop_flags = @(preg_match($regex, $configfile))?false:true;
@@ -367,7 +367,7 @@ class installer_dist extends installer_base {
 		$config_dir = $conf['postfix']['config_dir'];
 		//* Configure master.cf and add a line for deliver
 		if ($this->postfix_master()) {
-			exec ("postconf -M dovecot.unix", $out, $ret);
+			exec ("postconf -M dovecot.unix &> /dev/null", $out, $ret);
 			$add_dovecot_service = @($out[0]=='')?true:false;
 		} else { //* fallback - postfix < 2.9
 			$content = rf($config_dir.'/master.cf');
@@ -503,13 +503,13 @@ class installer_dist extends installer_base {
 
 		// Adding amavis-services to the master.cf file if the service does not already exists
 		if ($this->postfix_master()) {
-			exec ("postconf -M amavis.unix", $out, $ret);
+			exec ("postconf -M amavis.unix &> /dev/null", $out, $ret);
 			$add_amavis = @($out[0]=='')?true:false;
 			unset($out);
-			exec ("postconf -M 127.0.0.1:10025.inet", $out, $ret);
+			exec ("postconf -M 127.0.0.1:10025.inet &> /dev/null", $out, $ret);
 			$add_amavis_10025 = @($out[0]=='')?true:false;
 			unset($out);
-			exec ("postconf -M 127.0.0.1:10027.inet", $out, $ret);
+			exec ("postconf -M 127.0.0.1:10027.inet &> /dev/null", $out, $ret);
 			$add_amavis_10027 = @($out[0]=='')?true:false;
 			unset($out);
 		} else { //* fallback - postfix < 2.9