diff --git a/default.nix b/default.nix
index a2158a6..5b5e015 100644
--- a/default.nix
+++ b/default.nix
@@ -172,7 +172,7 @@ in
       '';
     };
 
-    cert_dir = mkOption {
+    certificateDirectory = mkOption {
       type = types.path;
       default = "/var/certs";
       description = ''
@@ -183,7 +183,7 @@ in
       '';
     };
 
-    enable_imap = mkOption {
+    enableImap = mkOption {
       type = types.bool;
       default = true;
       description = ''
@@ -196,7 +196,7 @@ in
       '';
     };
 
-    enable_pop3 = mkOption {
+    enablePop3 = mkOption {
       type = types.bool;
       default = false;
       description = ''
@@ -221,7 +221,7 @@ in
       '';
     };
 
-    dkim_signing = mkOption {
+    dkimSigning = mkOption {
       type = types.bool;
       default = true;
       description = ''
@@ -230,7 +230,7 @@ in
       '';
     };
 
-    dkim_selector = mkOption {
+    dkimSelector = mkOption {
       type = types.string;
       default = "mail";
       description = ''
@@ -238,7 +238,7 @@ in
       '';
     };
 
-    dkim_dir = mkOption {
+    dkimKeyDirectory = mkOption {
       type = types.path;
       default = "/var/dkim";
       description = ''
@@ -255,8 +255,8 @@ in
     services = import ./mail-server/services.nix {
       inherit lib;
       inherit (cfg) mailDirectory vmailUserName vmailGroupName virtualAliases domain
-              enable_imap enable_pop3 dkim_signing dkim_selector dkim_dir
-              certificateScheme certificateFile keyFile cert_dir virusScanning;
+              enableImap enablePop3 dkimSigning dkimSelector dkimKeyDirectory
+              certificateScheme certificateFile keyFile certificateDirectory virusScanning;
     };
 
     environment = import ./mail-server/environment.nix {
@@ -265,13 +265,14 @@ in
     };
 
     networking = import ./mail-server/networking.nix {
-      inherit (cfg) domain hostPrefix enable_imap enable_pop3;
+      inherit (cfg) domain hostPrefix enableImap enablePop3;
     };
 
     systemd = import ./mail-server/systemd.nix {
       inherit pkgs;
-      inherit (cfg) mailDirectory vmailGroupName certificateScheme cert_dir
-              hostPrefix domain dkim_selector dkim_dir;
+      inherit (cfg) mailDirectory vmailGroupName certificateScheme
+      certificateDirectory
+              hostPrefix domain dkimSelector dkimKeyDirectory;
     };
 
     users = import ./mail-server/users.nix {
diff --git a/mail-server/dovecot.nix b/mail-server/dovecot.nix
index d94539e..15d08ee 100644
--- a/mail-server/dovecot.nix
+++ b/mail-server/dovecot.nix
@@ -14,7 +14,7 @@
 #  You should have received a copy of the GNU General Public License
 #  along with this program. If not, see <http://www.gnu.org/licenses/>
 
-{ vmailGroupName, vmailUserName, mailDirectory, enable_imap, enable_pop3, cert,
+{ vmailGroupName, vmailUserName, mailDirectory, enableImap, enablePop3, cert,
 key }:
 
 let
@@ -24,8 +24,8 @@ let
 in
 {
   enable = true;
-  enableImap = enable_imap;
-  enablePop3 = enable_pop3;
+  enableImap = enableImap;
+  enablePop3 = enablePop3;
   mailGroup = vmailGroupName;
   mailUser = vmailUserName;
   mailLocation = dovecot_maildir;
diff --git a/mail-server/networking.nix b/mail-server/networking.nix
index 81c2d15..750f2e8 100644
--- a/mail-server/networking.nix
+++ b/mail-server/networking.nix
@@ -14,7 +14,7 @@
 #  You should have received a copy of the GNU General Public License
 #  along with this program. If not, see <http://www.gnu.org/licenses/>
 
-{ domain, hostPrefix, enable_imap, enable_pop3 }:
+{ domain, hostPrefix, enableImap, enablePop3 }:
 
 {
   #hostName = "${hostPrefix}.${domain}";
@@ -22,7 +22,7 @@
   firewall = {
     enable = true;
     allowedTCPPorts = [ 25 587 ]
-      ++ (if enable_imap then [ 143 ] else [])
-      ++ (if enable_pop3 then [ 110 ] else []);
+      ++ (if enableImap then [ 143 ] else [])
+      ++ (if enablePop3 then [ 110 ] else []);
   };
 }
diff --git a/mail-server/rmilter.nix b/mail-server/rmilter.nix
index ea62a9f..d003779 100644
--- a/mail-server/rmilter.nix
+++ b/mail-server/rmilter.nix
@@ -14,7 +14,7 @@
 #  You should have received a copy of the GNU General Public License
 #  along with this program. If not, see <http://www.gnu.org/licenses/>
 
-{ domain, virusScanning, dkim_signing, dkim_dir, dkim_selector }:
+{ domain, virusScanning, dkimSigning, dkimKeyDirectory, dkimSelector }:
 
 let
   clamav = if virusScanning
@@ -25,14 +25,14 @@ let
              };
            ''
            else "";
-  dkim = if dkim_signing
+  dkim = if dkimSigning
          then
          ''
             dkim {
               domain {
-                key = "${dkim_dir}";
+                key = "${dkimKeyDirectory}";
                 domain = "*";
-                selector = "${dkim_selector}";
+                selector = "${dkimSelector}";
               };
               sign_alg = sha256;
               auth_only = yes;
diff --git a/mail-server/services.nix b/mail-server/services.nix
index 7d2188c..c17b961 100644
--- a/mail-server/services.nix
+++ b/mail-server/services.nix
@@ -14,23 +14,24 @@
 #  You should have received a copy of the GNU General Public License
 #  along with this program. If not, see <http://www.gnu.org/licenses/>
 
-{ lib, mailDirectory, vmailUserName, vmailGroupName, virtualAliases, domain, enable_imap,
-enable_pop3, virusScanning, dkim_signing, dkim_selector, dkim_dir,
-certificateScheme, certificateFile, keyFile, cert_dir }:
+{ lib, mailDirectory, vmailUserName, vmailGroupName, virtualAliases, domain,
+enableImap, enablePop3, virusScanning, dkimSigning, dkimSelector,
+dkimKeyDirectory, certificateScheme, certificateFile, keyFile,
+certificateDirectory }:
 
 let
   # cert :: PATH
   cert = if certificateScheme == 1
          then certificateFile
          else if certificateScheme == 2
-              then "${cert_dir}/cert-${domain}.pem"
+              then "${certificateDirectory}/cert-${domain}.pem"
               else "";
 
   # key :: PATH
   key = if certificateScheme == 1
         then keyFile
         else if certificateScheme == 2
-             then "${cert_dir}/key-${domain}.pem"
+             then "${certificateDirectory}/key-${domain}.pem"
              else "";
 in
 {
@@ -40,7 +41,7 @@ in
   };
 
   rmilter = import ./rmilter.nix {
-    inherit domain virusScanning dkim_signing dkim_selector dkim_dir;
+    inherit domain virusScanning dkimSigning dkimSelector dkimKeyDirectory;
   };
 
   postfix = import ./postfix.nix {
@@ -48,7 +49,7 @@ in
   };
 
   dovecot2 = import ./dovecot.nix {
-    inherit vmailGroupName vmailUserName mailDirectory enable_imap
-            enable_pop3 cert key;
+    inherit vmailGroupName vmailUserName mailDirectory enableImap
+            enablePop3 cert key;
   };
 }
diff --git a/mail-server/systemd.nix b/mail-server/systemd.nix
index fe3c688..24d4a7e 100644
--- a/mail-server/systemd.nix
+++ b/mail-server/systemd.nix
@@ -14,14 +14,14 @@
 #  You should have received a copy of the GNU General Public License
 #  along with this program. If not, see <http://www.gnu.org/licenses/>
 
-{ pkgs, mailDirectory, vmailGroupName, certificateScheme, cert_dir, hostPrefix,
-domain, dkim_selector, dkim_dir}:
+{ pkgs, mailDirectory, vmailGroupName, certificateScheme, certificateDirectory, hostPrefix,
+domain, dkimSelector, dkimKeyDirectory}:
 
 let
   create_certificate = if certificateScheme == 2 then
         ''
           # Create certificates if they do not exist yet
-          dir="${cert_dir}"
+          dir="${certificateDirectory}"
           fqdn="${hostPrefix}.${domain}"
           case $fqdn in /*) fqdn=$(cat "$fqdn");; esac
           key="''${dir}/key-${domain}.pem";
@@ -29,7 +29,7 @@ let
 
           if [ ! -f "''${key}" ] || [ ! -f "''${cert}" ]
           then
-              mkdir -p "${cert_dir}"
+              mkdir -p "${certificateDirectory}"
               (umask 077; "${pkgs.openssl}/bin/openssl" genrsa -out "''${key}" 2048) &&
                   "${pkgs.openssl}/bin/openssl" req -new -key "''${key}" -x509 -subj "/CN=''${fqdn}" \
                           -days 3650 -out "''${cert}"
@@ -37,20 +37,20 @@ let
         ''
         else "";
 
-  dkim_key = "${dkim_dir}/${dkim_selector}.private";
-  dkim_txt = "${dkim_dir}/${dkim_selector}.txt";
+  dkim_key = "${dkimKeyDirectory}/${dkimSelector}.private";
+  dkim_txt = "${dkimKeyDirectory}/${dkimSelector}.txt";
   create_dkim_cert =
         ''
           # Create dkim dir
-          mkdir -p "${dkim_dir}"
-          chown rmilter:rmilter "${dkim_dir}"
+          mkdir -p "${dkimKeyDirectory}"
+          chown rmilter:rmilter "${dkimKeyDirectory}"
 
           if [ ! -f "${dkim_key}" ] || [ ! -f "${dkim_txt}" ]
           then
 
-              ${pkgs.opendkim}/bin/opendkim-genkey -s "${dkim_selector}" \
+              ${pkgs.opendkim}/bin/opendkim-genkey -s "${dkimSelector}" \
                                                    -d ${domain} \
-                                                   --directory="${dkim_dir}"
+                                                   --directory="${dkimKeyDirectory}"
               chown rmilter:rmilter "${dkim_key}"
           fi
         '';