diff --git a/README.markdown b/README.markdown
index dbe53bc..1292df0 100644
--- a/README.markdown
+++ b/README.markdown
@@ -43,6 +43,7 @@ class {'postfix':
 * `relayhost_port` This sets the port for the relay host specified with the `relayhost` parameter. The default is `undef` which leaves the port specifier off the end of the relayhost setting. This parameter does nothing if the `relayhost` parameter is not set.
 * `daemon_directory` Sets the directory with Postfix support programs and daemon programs are installed. The default is specific for each operating system. It's _not_ recommended that this parameter be changed.
 * `inet_interfaces` Sets the network interface for postfix to bind do. The default value is `localhost`
+* `inet_protocols` Sets the network internet protocol for postfix to utilise. The default value is `all`
 
 # Attribution
 
diff --git a/manifests/init.pp b/manifests/init.pp
index 4aca743..3de5f0c 100644
--- a/manifests/init.pp
+++ b/manifests/init.pp
@@ -35,6 +35,7 @@
   $relayhost_port   = undef,
   $daemon_directory = $::postfix::params::daemon_directory,
   $inet_interfaces  = $::postfix::params::inet_interfaces,
+  $inet_protocols   = $::postfix::params::inet_protocols,
 ) inherits postfix::params {
 
   if $remove_sendmail {
diff --git a/manifests/params.pp b/manifests/params.pp
index c43806e..55c0298 100644
--- a/manifests/params.pp
+++ b/manifests/params.pp
@@ -48,4 +48,5 @@
   $sendmailcf_package = 'sendmail-cf'
   $sendmail_service   = 'sendmail'
   $inet_interfaces    = 'localhost'
+  $inet_protocols     = 'all'
 }
diff --git a/spec/classes/postfix_spec.rb b/spec/classes/postfix_spec.rb
index 6cc0d49..b5b5af6 100644
--- a/spec/classes/postfix_spec.rb
+++ b/spec/classes/postfix_spec.rb
@@ -98,6 +98,15 @@
         ) }
       end
 
+      describe 'when setting inet_protocols' do
+        let :params do
+          { :inet_protocols => 'all' }
+        end
+        it { should contain_file('postfix_config').with_content(
+          %r{^inet_protocols = all$}
+        ) }
+      end
+
     end
   end
   
diff --git a/templates/main.cf.erb b/templates/main.cf.erb
index 0377e4f..1aa44ed 100644
--- a/templates/main.cf.erb
+++ b/templates/main.cf.erb
@@ -120,8 +120,12 @@ myorigin = <%= @myorigin %>
 #inet_interfaces = $myhostname, localhost
 inet_interfaces = <%= @inet_interfaces %>
 
-# Enable IPv4, and IPv6 if supported
-inet_protocols = all
+# Enable IPv4 and/or IPv6
+# Options:
+# all  - IPv4 and IPv6
+# ipv4 - IPv4 only
+# ipv6 - IPv6 only
+inet_protocols = <%= @inet_protocols %>
 
 # The proxy_interfaces parameter specifies the network interface
 # addresses that this mail system receives mail on by way of a