diff --git a/postfix/manifests/init.pp b/postfix/manifests/init.pp
index 8643ebf..892e625 100644
--- a/postfix/manifests/init.pp
+++ b/postfix/manifests/init.pp
@@ -1,5 +1,34 @@
 # Install Postfix packages.
 #
+# === Global variables
+#
+#   $mail_domain:
+#       SMTP domain name.
+#
+#   $mail_server:
+#       Optional smarthost used for sending mail.
+#
+#   $postfix_hostname:
+#       Hostname of postfix server. Defaults to $fqdn.
+#
+#   $postfix_interfaces:
+#       Interfaces to listen. Defaults to 'localhost'.
+#
+#   $postfix_networks:
+#       Optional value for mynetworks variable.
+#
+#   $postfix_home_mailbox:
+#       Optional value for home_mailbox variable.
+#
+#   $postfix_rbl:
+#       List of RBL hosts to use.
+#
+#   $postfix_key:
+#       Path to SSL private key. Defaults to puppet client key.
+#
+#   $postfix_cert:
+#       Path to SSL certificate. Defaults to puppet client certificate.
+#
 class postfix {
 
     include ssl
diff --git a/postfix/templates/main.cf.erb b/postfix/templates/main.cf.erb
index 8310ae6..4f0c6ac 100644
--- a/postfix/templates/main.cf.erb
+++ b/postfix/templates/main.cf.erb
@@ -270,6 +270,9 @@ mynetworks_style = subnet
 #mynetworks = 168.100.189.0/28, 127.0.0.0/8
 #mynetworks = $config_directory/mynetworks
 #mynetworks = hash:/etc/postfix/network_table
+<% if has_variable?("postfix_networks") -%>
+mynetworks = <%= postfix_networks %>
+<% end -%>
 
 # The relay_domains parameter restricts what destinations this system will
 # relay mail to.  See the smtpd_recipient_restrictions description in
@@ -429,7 +432,7 @@ alias_database = hash:/etc/aliases
 #home_mailbox = Mailbox
 #home_mailbox = Maildir/
 <% if has_variable?("postfix_home_mailbox") -%>
-home_mailbox <%= postfix_home_mailbox %>
+home_mailbox = <%= postfix_home_mailbox %>
 <% end -%>
  
 # The mail_spool_directory parameter specifies the directory where