diff --git a/install/dist/lib/gentoo.lib.php b/install/dist/lib/gentoo.lib.php
index 69691a6afd7c34f1ed1baa89ddd0f867e0653499..7b5210f01343b000da32eaeb5347c94d385051ba 100644
--- a/install/dist/lib/gentoo.lib.php
+++ b/install/dist/lib/gentoo.lib.php
@@ -427,15 +427,15 @@ class installer extends installer_base
 		foreach ($options as $value) {
 			$value = trim($value);
 			if ($value == '') continue;
-			if (preg_match("|check_recipient_access\s+proxy:mysql:${quoted_config_dir}/mysql-verify_recipients.cf|", $value)) {
+      if (preg_match("|check_recipient_access\s+proxy:mysql:{$quoted_config_dir}/mysql-verify_recipients.cf|", $value)) {
 				continue;
 			}
 			$new_options[] = $value;
 		}
-		if ($configure_lmtp && $conf['mail']['content_filter'] === 'amavisd') {
+    if ($configure_lmtp && (!isset($conf['mail']['content_filter']) || $conf['mail']['content_filter'] === 'amavisd')) {
 			for ($i = 0; isset($new_options[$i]); $i++) {
 				if ($new_options[$i] == 'reject_unlisted_recipient') {
-					array_splice($new_options, $i+1, 0, array("check_recipient_access proxy:mysql:${config_dir}/mysql-verify_recipients.cf"));
+          array_splice($new_options, $i+1, 0, array("check_recipient_access proxy:mysql:{$config_dir}/mysql-verify_recipients.cf"));
 					break;
 				}
 			}
@@ -502,20 +502,26 @@ class installer extends installer_base
 
 				// Check if we have a dhparams file and if not, create it
 				if(!file_exists('/etc/dovecot/dh.pem')) {
-					swriteln('Creating new DHParams file, this takes several minutes. Do not interrupt the script.');
+					// Create symlink to ISPConfig dhparam file
+					swriteln('Creating symlink /etc/dovecot/dh.pem to ISPConfig DHParam file.');
+					symlink('/usr/local/ispconfig/interface/ssl/dhparam4096.pem', '/etc/dovecot/dh.pem');
+          
+          /*
+          swriteln('Creating new DHParams file, this takes several minutes. Do not interrupt the script.');
 					if(file_exists('/var/lib/dovecot/ssl-parameters.dat')) {
 						// convert existing ssl parameters file
 						$command = 'dd if=/var/lib/dovecot/ssl-parameters.dat bs=1 skip=88 | openssl dhparam -inform der > /etc/dovecot/dh.pem';
 						caselog($command.' &> /dev/null', __FILE__, __LINE__, "EXECUTED: $command", "Failed to execute the command $command");
 					} else {
-						/*
-						   Create a new dhparams file. We use 2048 bit only as it simply takes too long
-						   on smaller systems to generate a 4096 bit dh file (> 30 minutes). If you need
-						   a 4096 bit file, create it manually before you install ISPConfig
-						*/
+						
+						   //Create a new dhparams file. We use 2048 bit only as it simply takes too long
+						   //on smaller systems to generate a 4096 bit dh file (> 30 minutes). If you need
+						  // a 4096 bit file, create it manually before you install ISPConfig
+						
 						$command = 'openssl dhparam -out /etc/dovecot/dh.pem 2048';
 						caselog($command.' &> /dev/null', __FILE__, __LINE__, "EXECUTED: $command", "Failed to execute the command $command");
 					}
+          */
 				}
 				//remove #2.3+ comment
 				$content = file_get_contents($config_dir.'/'.$configfile);