diff --git a/install_postfix_advanced.sh b/install_postfix_advanced.sh
index f576533..2072cc4 100755
--- a/install_postfix_advanced.sh
+++ b/install_postfix_advanced.sh
@@ -1784,9 +1784,6 @@ smtpd_tls_key_file = $_TLS_KEY_FILE
 ## - Dont't forget to create it, e.g with openssl:
 ## -    openssl dhparam -out /etc/postfix/ssl/dh_1024.pem -2 1024
 ## -
-## - or using '-dsaparam' to avoid long creation time:
-## -    openssl dhparam -dsaparam -out /etc/postfix/ssl/dh_1024.pem 1024
-## -
 #smtpd_tls_dh1024_param_file = /etc/postfix/ssl/dh_1024.pem
 ## - also possible to use 2048 key with that parameter
 ## -
@@ -1797,9 +1794,6 @@ smtpd_tls_dh1024_param_file = /etc/postfix/ssl/dh_2048.pem
 ## - Dont't forget to create it, e.g with openssl:
 ## -    openssl dhparam -out /etc/postfix/ssl/dh_512.pem -2 512
 ## -
-## - or using '-dsaparam' to avoid long creation time:
-## -    openssl dhparam -dsaparam -out /etc/postfix/ssl/dh_512.pem 512
-## -
 smtpd_tls_dh512_param_file = /etc/postfix/ssl/dh_512.pem
 
 
@@ -2627,8 +2621,8 @@ fi
 ## -
 echononl "   Generate DH key length=512 \"/etc/postfix/ssl/dh_512.pem\""
 if [ ! -f /etc/postfix/ssl/dh_512.pem ]; then
-   #openssl dhparam -out /etc/postfix/ssl/dh_512.pem -2 512 > /dev/null 2>&1
-   openssl dhparam -dsaparam -out /etc/postfix/ssl/dh_512.pem 512 > /dev/null 2>&1
+   openssl dhparam -out /etc/postfix/ssl/dh_512.pem -2 512 > /dev/null 2>&1
+   #openssl dhparam -dsaparam -out /etc/postfix/ssl/dh_512.pem 512 > /dev/null 2>&1
    if [[ $? -eq 0 ]] ; then
       echo_ok
    else
@@ -2639,8 +2633,8 @@ else
 fi
 echononl "   Generate DH key length=1024 \"/etc/postfix/ssl/dh_1024.pem\""
 if [ ! -f /etc/postfix/ssl/dh_1024.pem ]; then
-   #openssl dhparam -out /etc/postfix/ssl/dh_1024.pem -2 1024 > /dev/null 2>&1
-   openssl dhparam -dsaparam -out /etc/postfix/ssl/dh_1024.pem 1024 > /dev/null 2>&1
+   openssl dhparam -out /etc/postfix/ssl/dh_1024.pem -2 1024 > /dev/null 2>&1
+   #openssl dhparam -dsaparam -out /etc/postfix/ssl/dh_1024.pem 1024 > /dev/null 2>&1
    if [[ $? -eq 0 ]] ; then
       echo_ok
    else
@@ -2651,8 +2645,8 @@ else
 fi
 echononl "   Generate DH key length=2048 \"/etc/postfix/ssl/dh_2048.pem\""
 if [ ! -f /etc/postfix/ssl/dh_2048.pem ]; then
-   #openssl dhparam -out /etc/postfix/ssl/dh_2048.pem -2 2048 > /dev/null 2>&1
-   openssl dhparam -dsaparam -out /etc/postfix/ssl/dh_2048.pem 2048 > /dev/null 2>&1
+   openssl dhparam -out /etc/postfix/ssl/dh_2048.pem -2 2048 > /dev/null 2>&1
+   #openssl dhparam -dsaparam -out /etc/postfix/ssl/dh_2048.pem 2048 > /dev/null 2>&1
    if [[ $? -eq 0 ]] ; then
       echo_ok
    else
diff --git a/install_postfix_base.sh b/install_postfix_base.sh
index c6ecefb..836a0a3 100755
--- a/install_postfix_base.sh
+++ b/install_postfix_base.sh
@@ -78,6 +78,43 @@ echo_skipped() {
    echo -e "\033[80G[ \033[33m\033[1mskipped\033[m ]"
 }
 
+blank_line() {
+   if $terminal ; then
+      echo ""
+   fi
+}
+
+
+detect_os () {
+
+   if $(which lsb_release > /dev/null 2>&1) ; then
+
+      DIST="$(lsb_release -i | awk '{print tolower($3)}')"
+      DIST_VERSION="$(lsb_release -r | awk '{print tolower($2)}')"
+      DIST_CODENAME="$(lsb_release -c | awk '{print tolower($2)}')"
+
+      if [[ "$DIST" = "debian" ]]; then
+         if $(echo "$DIST_VERSION" | grep -q '\.') ; then
+            DIST_VERSION=$(echo "$DIST_VERSION" | cut --delimiter='.' -f1)
+         fi
+      fi
+
+   elif [[ -e "/etc/os-release" ]]; then
+
+      . /etc/os-release
+
+      DIST=$ID
+      DIST_VERSION=${VERSION_ID}
+
+   fi
+
+   # remove whitespace from DIST and DIST_VERSION
+   DIST="${DIST// /}"
+   DIST_VERSION="${DIST_VERSION// /}"
+
+}
+
+
 
 # -------------
 # --- Some default settings
@@ -118,8 +155,19 @@ if [[ -z "$_HOSTNAME" ]] ; then
    [[ "$_HOSTNAME" = "$_HOSTNAME_SHORT" ]] && _HOSTNAME=""
 fi
 
+blank_line
+echononl "Detect distribution/release of running OS.."
+detect_os  > /dev/null 2>&1
+if [[ $? -ne 0 ]]; then
+   echo_failed
+else
+   echo_ok
+fi
+blank_line
+blank_line
 
-clear
+
+#clear
 echo -e "\033[21G\033[32mInstallation script for Postfix basic mailsystem \033[m"
 echo
 
@@ -998,40 +1046,82 @@ fi
 ## - with EDH ciphers (length 512 and 1024
 ## -
 echononl "   Generate DH key length=512 \"/etc/postfix/ssl/dh_512.pem\""
-if [ ! -f /etc/postfix/ssl/dh_512.pem ]; then
-   #openssl dhparam -out /etc/postfix/ssl/dh_512.pem -2 512 > /dev/null 2>&1
-   openssl dhparam -dsaparam -out /etc/postfix/ssl/dh_512.pem 512 > /dev/null 2>&1
+if [[ ! -f /etc/postfix/ssl/dh_512.pem ]]; then
+   if [[ $DIST_VERSION -gt 11 ]] ; then
+      openssl dhparam -out /etc/postfix/ssl/dh_512.pem 512 > /dev/null 2>&1
+   else
+      openssl dhparam -dsaparam -out /etc/postfix/ssl/dh_512.pem 512 > /dev/null 2>&1
+   fi
    if [[ $? -eq 0 ]] ; then
       echo_ok
    else
       echo_failed
    fi
 else
-   echo_skipped
+   if [[ $DIST_VERSION -gt 11 ]] ; then
+      if $(grep -q -E "X9.42" /etc/postfix/ssl/dh_512.pem 2> /dev/null); then
+         openssl dhparam -out /etc/postfix/ssl/dh_512.pem 512 > /dev/null 2>&1
+         if [[ $? -eq 0 ]] ; then
+            echo_ok
+         else
+            echo_failed
+         fi
+      fi
+   else
+      echo_skipped
+   fi
 fi
 echononl "   Generate DH key length=1024 \"/etc/postfix/ssl/dh_1024.pem\""
-if [ ! -f /etc/postfix/ssl/dh_1024.pem ]; then
-   #openssl dhparam -out /etc/postfix/ssl/dh_1024.pem -2 1024 > /dev/null 2>&1
-   openssl dhparam -dsaparam -out /etc/postfix/ssl/dh_1024.pem 1024 > /dev/null 2>&1
+if [[ ! -f /etc/postfix/ssl/dh_1024.pem ]]; then
+   if [[ $DIST_VERSION -gt 11 ]] ; then
+      openssl dhparam -out /etc/postfix/ssl/dh_1024.pem 1024 > /dev/null 2>&1
+   else
+      openssl dhparam -dsaparam -out /etc/postfix/ssl/dh_1024.pem 1024 > /dev/null 2>&1
+   fi
    if [[ $? -eq 0 ]] ; then
       echo_ok
    else
       echo_failed
    fi
 else
-   echo_skipped
+   if [[ $DIST_VERSION -gt 11 ]] ; then
+      if $(grep -q -E "X9.42" /etc/postfix/ssl/dh_1024.pem 2> /dev/null); then
+         openssl dhparam -out /etc/postfix/ssl/dh_1024.pem 1024 > /dev/null 2>&1
+         if [[ $? -eq 0 ]] ; then
+            echo_ok
+         else
+            echo_failed
+         fi
+      fi
+   else
+      echo_skipped
+   fi
 fi
 echononl "   Generate DH key length=2048 \"/etc/postfix/ssl/dh_2048.pem\""
-if [ ! -f /etc/postfix/ssl/dh_2048.pem ]; then
-   #openssl dhparam -out /etc/postfix/ssl/dh_2048.pem -2 2048 > /dev/null 2>&1
-   openssl dhparam -dsaparam -out /etc/postfix/ssl/dh_2048.pem 2048 > /dev/null 2>&1
+if [[ ! -f /etc/postfix/ssl/dh_2048.pem ]]; then
+   if [[ $DIST_VERSION -gt 11 ]] ; then
+      openssl dhparam -out /etc/postfix/ssl/dh_2048.pem 2048 > /dev/null 2>&1
+   else
+      openssl dhparam -dsaparam -out /etc/postfix/ssl/dh_2048.pem 2048 > /dev/null 2>&1
+   fi
    if [[ $? -eq 0 ]] ; then
       echo_ok
    else
       echo_failed
    fi
 else
-   echo_skipped
+   if [[ $DIST_VERSION -gt 11 ]] ; then
+      if $(grep -q -E "X9.42" /etc/postfix/ssl/dh_2048.pem 2> /dev/null); then
+         openssl dhparam -out /etc/postfix/ssl/dh_2048.pem 2048 > /dev/null 2>&1
+         if [[ $? -eq 0 ]] ; then
+            echo_ok
+         else
+            echo_failed
+         fi
+      fi
+   else
+      echo_skipped
+   fi
 fi
 echononl "   Create Symlink \"$_TLS_CERT_FILE\""
 if [ ! -h "$_TLS_CERT_FILE" ]; then