diff --git a/manifests/init.pp b/manifests/init.pp
index db2a097a70c6391c6e8f37f9a8bfce990ead6d14..0af6148b888676c40a287c12c34e81a78ee5b1a2 100644
--- a/manifests/init.pp
+++ b/manifests/init.pp
@@ -82,7 +82,7 @@ class postfix (
   $master_submission   = undef,         # postfix_master_submission
   $mta                 = false,
   $mydestination       = '$myorigin',   # postfix_mydestination
-  $mynetworks          = '127.0.0.0/8', # postfix_mynetworks
+  $mynetworks          = '127.0.0.0/8 [::ffff:127.0.0.0]/104 [::1]/128', # postfix_mynetworks
   $myorigin            = $::fqdn,
   $relayhost           = undef,         # postfix_relayhost
   $root_mail_recipient = 'nobody',      # root_mail_recipient
diff --git a/spec/classes/postfix_spec.rb b/spec/classes/postfix_spec.rb
index f5e684f4adb49c8294e83c4a4b241f424f511324..6964e7958147c3eea8cfa706397d7ae750b55538 100644
--- a/spec/classes/postfix_spec.rb
+++ b/spec/classes/postfix_spec.rb
@@ -214,7 +214,7 @@ describe 'postfix' do
         let (:params) { { :mta => true, :mydestination => '1.2.3.4', :relayhost => '2.3.4.5' } }
         it 'should configure postfix as a minimal MTA, delivering mail to the mydestination param' do
           is_expected.to contain_postfix__config('mydestination').with_value('1.2.3.4')
-          is_expected.to contain_postfix__config('mynetworks').with_value('127.0.0.0/8')
+          is_expected.to contain_postfix__config('mynetworks').with_value('127.0.0.0/8 [::ffff:127.0.0.0]/104 [::1]/128')
           is_expected.to contain_postfix__config('relayhost').with_value('2.3.4.5')
           is_expected.to contain_postfix__config('virtual_alias_maps').with_value('hash:/etc/postfix/virtual')
           is_expected.to contain_postfix__config('transport_maps').with_value('hash:/etc/postfix/transport')
@@ -261,7 +261,7 @@ describe 'postfix' do
         end
         it 'should configure all local email to be forwarded to $root_mail_recipient delivered through $relayhost' do
           is_expected.to contain_postfix__config('mydestination').with_value('1.2.3.4')
-          is_expected.to contain_postfix__config('mynetworks').with_value('127.0.0.0/8')
+          is_expected.to contain_postfix__config('mynetworks').with_value('127.0.0.0/8 [::ffff:127.0.0.0]/104 [::1]/128')
           is_expected.to contain_postfix__config('relayhost').with_value('2.3.4.5')
           is_expected.to contain_postfix__config('virtual_alias_maps').with_value('hash:/etc/postfix/virtual')
           is_expected.to contain_postfix__config('transport_maps').with_value('hash:/etc/postfix/transport')