diff --git a/edh-keygen.conf b/edh-keygen.conf
index 4fc61a3..612088d 100644
--- a/edh-keygen.conf
+++ b/edh-keygen.conf
@@ -5,14 +5,31 @@
 #
 #   tls_tmp_path     - Temporary folder for DH key generation
 #   tls_private_path - Folder where DH keys are stored permanently
+#   key_sizes        - (Optional) Space-separated list of DH key sizes to generate.
 #
 # If omitted, the following defaults are used:
 #   tls_tmp_path=/etc/pki/tls/tmp
 #   tls_private_path=/etc/pki/tls/private/
 #
+# key_sizes usage:
+#   You can define a global list of Diffie-Hellman key sizes to generate by
+#   setting the 'key_sizes' parameter at the top of this file. This allows you
+#   to explicitly control which DH parameter sizes are created, regardless of
+#   the sizes specified in individual service lines.
+#
+#   Example:
+#     key_sizes=2048 4096
+#
+#   - This will instruct the script to generate DH parameters for 2048
+#     and 4096 bits.
+#   - If 'key_sizes' is not set, the script will automatically extract all key
+#     sizes used in the service definitions and generate those.
+#   - Use a space-separated list for multiple sizes.
+#
 # Example:
 #   tls_tmp_path=/etc/pki/tls/tmp
 #   tls_private_path=/etc/pki/tls/private/
+#   key_sizes=2048 4096
 #
 # -----------------------------------------------------------------------------
 #
@@ -57,6 +74,7 @@
 # Global settings
 #tls_tmp_path=/etc/pki/tls/tmp
 #tls_private_path=/etc/pki/tls/private/
+#key_sizes=2048 4096
 
 # Service lines
 #dovecot:root
diff --git a/edh-keygen.sh b/edh-keygen.sh
index 331c399..11bfa65 100644
--- a/edh-keygen.sh
+++ b/edh-keygen.sh
@@ -7,9 +7,9 @@
 # Diffie-Hellman Key Generation and Service Management Script
 #
 # This script generates Diffie-Hellman parameter files for various key sizes,
-# manages their permissions, and can synchronize keys to custom locations
+# manages their permissions and can synchronize keys to custom locations
 # with specified ownership and permissions. It supports service restarts
-# for both root and non-root systemd users, and is designed for integration
+# for both root and non-root systemd users and is designed for integration
 # with automated cron jobs.
 #
 # Configuration is read from a .conf or .local file, supporting per-service
@@ -37,8 +37,8 @@
 # Permission is hereby granted, free of charge, to any person obtaining a copy
 # of this software and associated documentation files (the "Software"), to deal
 # in the Software without restriction, including without limitation the rights
-# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
-# copies of the Software, and to permit persons to whom the Software is
+# to use, copy, modify, merge, publish, distribute, sublicense and/or sell
+# copies of the Software and to permit persons to whom the Software is
 # furnished to do so, subject to the following conditions:
 #
 # The above copyright notice and this permission notice shall be included in all
@@ -74,10 +74,11 @@ fi
 # Read global settings from config file
 while IFS= read -r line || [ -n "$line" ]; do
     case "$line" in
-        ''|\#*) continue ;;
+        ''|\#*) continue ;; # Skip empty lines and comments
         tls_tmp_path=*) tls_tmp_path="${line#tls_tmp_path=}" ;;
         tls_private_path=*) tls_private_path="${line#tls_private_path=}" ;;
-        *) break ;; # Stop at first non-global line
+        key_sizes=*) key_sizes="${line#key_sizes=}" ;;
+        *) break ;; # Stop at first non-global line (service lines start here)
     esac
 done < "$my_service_conf"
 
@@ -88,8 +89,15 @@ fi
 
 umask 022
 
+# If key_sizes is set in the config, use it; otherwise, extract from service lines or set a default
+if [ -z "$key_sizes" ]; then
+    key_sizes=$(awk -F: 'NF >= 3 && $3 ~ /^[0-9]+$/ { print $3 }' "$my_service_conf" | sort -nu)
+    [ -z "$key_sizes" ] && key_sizes="2048 4096"
+fi
+
 # Generate DH params
-for bits in 512 1024 2048 4096; do
+for bits in $key_sizes; do
+    echo "Generating DH parameters for $bits bits..."
     openssl dhparam -out "$tls_tmp_path/dh_${bits}.pem" "$bits"
 done
 
@@ -109,7 +117,7 @@ while IFS= read -r line || [ -n "$line" ]; do
         ''|\#*) continue ;;
     esac
 
-    # Extract service, owner, and sync parameters
+    # Extract service, owner and sync parameters
     service=$(printf "%s" "$line" | awk -F: '{print $1}')
     owner=$(printf "%s" "$line" | awk -F: '{print $2}')
     key_size=$(printf "%s" "$line" | awk -F: '{print $3}')