diff --git a/README.md b/README.md
index 9ea4f56..0cab69a 100644
--- a/README.md
+++ b/README.md
@@ -180,7 +180,7 @@ user and .forward.
 - *Module Default*: '+'
 
 
-main_relayhost (default: empty)
+main_relayhost & main_relayhost_port (default: empty)
 -------------------------------
 The next-hop destination of non-local mail; overrides non-local domains in recipient addresses.
 This information is overruled with relay_transport, sender_dependent_default_transport_maps,
@@ -188,7 +188,8 @@ default_transport, sender_dependent_relayhost_maps and with the transport(5) tab
 In the case of SMTP, specify a domain name, hostname, hostname:port, [hostname]:port, [hostaddress]
 or [hostaddress]:port. The form [hostname] turns off MX lookups.
 
-- *Module Default*: "mailhost.${::domain}"
+- *Module Default* for host: "mailhost.${::domain}"
+- *Module Default* for port: '25'
 
 
 main_setgid_group (default: postdrop)
diff --git a/manifests/init.pp b/manifests/init.pp
index 714eed5..17f07e4 100644
--- a/manifests/init.pp
+++ b/manifests/init.pp
@@ -20,6 +20,7 @@
   $main_queue_directory     = 'USE_DEFAULTS',
   $main_recipient_delimiter = '+',
   $main_relayhost           = "mailhost.${::domain}",
+  $main_relayhost_port      = '25',
   $main_setgid_group        = 'USE_DEFAULTS',
   $packages                 = 'USE_DEFAULTS',
   $service_enable           = 'true',
@@ -113,7 +114,8 @@
     'USE_DEFAULTS' => $default_main_recipient_delimiter,
     default        => $main_recipient_delimiter }
 
-  $main_relayhost_real  = $main_relayhost
+  $main_relayhost_real      = $main_relayhost
+  $main_relayhost_port_real = $main_relayhost_port
 
   $main_setgid_group_real = $main_setgid_group ? {
     'USE_DEFAULTS' => $default_main_setgid_group,
@@ -151,6 +153,7 @@
   validate_absolute_path($main_queue_directory_real)
   # main_recipient_delimiter can not be checkek, it can contain nothing to everything
   if is_domain_name($main_relayhost_real) == false { fail("main_relayhost must be a domain name and is set to <${$main_relayhost_real}>") }
+  if is_integer($main_relayhost_port_real) == false { fail("main_relayhost_port must be an integer and is set to <${$main_relayhost_port_real}>") }
   if empty($main_setgid_group_real) == true { fail("main_setgid_group must contain a valid value and is set to <${main_setgid_group_real}>") }
   if empty($packages_real) == true { fail("packages must contain a valid value and is set to <${packages_real}>") }
   validate_re($service_enable_real, '^(true|false|manual)$', "service_enable may be either 'true', 'false' or 'manual' and is set to <${service_enable_real}>")
diff --git a/templates/main.cf.erb b/templates/main.cf.erb
index 6f709cb..170ebe5 100644
--- a/templates/main.cf.erb
+++ b/templates/main.cf.erb
@@ -51,7 +51,7 @@ queue_directory = <%= @main_queue_directory_real %>
 recipient_delimiter = <%= @main_recipient_delimiter_real %>
 
 # relayhost =
-relayhost = <%= @main_relayhost_real %>
+relayhost = <%= @main_relayhost_real %>:<%= @main_relayhost_port_real %>
 
 # setgid_group = postdrop
 setgid_group = <%= @main_setgid_group_real %>