diff --git a/exim/files/default/update-exim4.conf.conf b/exim/files/default/update-exim4.conf.conf
index cdabadd..1ea37b3 100644
--- a/exim/files/default/update-exim4.conf.conf
+++ b/exim/files/default/update-exim4.conf.conf
@@ -18,3 +18,6 @@ dc_minimaldns='{{ exim.minimaldns | lower }}'
 dc_readhost='{{ exim.readhost }}'
 dc_smarthost='{{ join_if_list(exim.smarthost) }}'
 CFILEMODE='{{ exim.cfilemode }}'
+{%- if exim.dc_mailname_in_oh %}
+dc_mailname_in_oh='{{ exim.dc_mailname_in_oh | lower }}'
+{% endif %}
diff --git a/pillar.example b/pillar.example
index 982781d..eda3f6e 100644
--- a/pillar.example
+++ b/pillar.example
@@ -16,6 +16,7 @@ exim:
     relay_domains: ''
     relay_nets: ''
     smarthost: ''
+    dc_mailname_in_oh: 'true'
   mailname: foo.bar.baz
   aliases:
     root: root@bar.baz
diff --git a/test/integration/default/controls/config_spec.rb b/test/integration/default/controls/config_spec.rb
index 90a3c25..c642d50 100644
--- a/test/integration/default/controls/config_spec.rb
+++ b/test/integration/default/controls/config_spec.rb
@@ -12,6 +12,7 @@
     its('content') { should include "dc_local_interfaces='127.0.0.1'" }
     its('content') { should include "dc_hide_mailname='false'" }
     its('content') { should include "dc_use_split_config='false'" }
+    its('content') { should include "dc_mailname_in_oh='true'" }
   end
 
   describe file('/etc/mailname') do
diff --git a/test/salt/pillar/exim.sls b/test/salt/pillar/exim.sls
index e78b55b..656d69f 100644
--- a/test/salt/pillar/exim.sls
+++ b/test/salt/pillar/exim.sls
@@ -6,6 +6,7 @@ exim:
     configtype: satellite
     hide_mailname: 'false'
     use_split_config: false
+    dc_mailname_in_oh: 'true'
     other_hostnames:
       - foo.bar.baz
       - bar.baz.foo