diff --git a/manifests/init.pp b/manifests/init.pp
index a3838eb..17e3d9e 100644
--- a/manifests/init.pp
+++ b/manifests/init.pp
@@ -21,15 +21,17 @@
 # http://www.exim.org/exim-html-current/doc/html/spec_html/index.html
 
 class exim(
-  $local_domains      = '@',
-  $mailman_domains    = [],
-  $queue_interval     = '30m',
-  $queue_run_max      = '5',
-  $queue_smtp_domains = undef,
-  $routers            = [],
-  $smarthost          = false,
-  $sysadmins          = [],
-  $transports         = [],
+  $local_domains            = '@',
+  $mailman_domains          = [],
+  $queue_interval           = '30m',
+  $queue_run_max            = '5',
+  $queue_smtp_domains       = undef,
+  $routers                  = [],
+  $smarthost                = false,
+  $sysadmins                = [],
+  $transports               = [],
+  $smtp_accept_max          = undef,
+  $smtp_accept_max_per_host = undef,
 ) {
 
   include ::exim::params
diff --git a/templates/exim4.conf.erb b/templates/exim4.conf.erb
index de9b63d..6f8bcf5 100644
--- a/templates/exim4.conf.erb
+++ b/templates/exim4.conf.erb
@@ -312,9 +312,9 @@ queue_run_max = <%= @queue_run_max %>
 # to be queued in this way, and is equivalent to setting
 # queue_smtp_domains to "*". See also hold_domains and queue_domains.
 
-<% if @queue_smtp_domains != "" -%>
+<% unless ["", nil, :undef].include?(@queue_smtp_domains) -%>
 queue_smtp_domains = <%= @queue_smtp_domains %>
-<% end %>
+<% end -%>
 
 <% if @mailman_domains.length > 0 -%>
 # Home dir for your Mailman installation -- aka Mailman's prefix
@@ -349,6 +349,16 @@ MM_LISTCHK=MM_HOME/lists/${lc::$local_part}/config.pck
 
 dns_ipv4_lookup = *.gmail.com : *.google.com
 
+<% unless ["", nil, :undef].include?(@smtp_accept_max) -%>
+# simultaneous incoming connections
+smtp_accept_max = <%= @smtp_accept_max %>
+<% end -%>
+
+<% unless ["", nil, :undef].include?(@smtp_accept_max_per_host) -%>
+# connections from one host
+smtp_accept_max_per_host = <%= @smtp_accept_max_per_host %>
+<% end -%>
+
 ######################################################################
 #                       ACL CONFIGURATION                            #
 #         Specifies access control lists for incoming SMTP mail      #