diff --git a/library/Icinga/Protocol/Ldap/LdapConnection.php b/library/Icinga/Protocol/Ldap/LdapConnection.php
index dd6c9b161..2b51ee4d7 100644
--- a/library/Icinga/Protocol/Ldap/LdapConnection.php
+++ b/library/Icinga/Protocol/Ldap/LdapConnection.php
@@ -1185,6 +1185,9 @@ class LdapConnection implements Selectable, Inspectable
             $ldapUrls = explode(' ', $hostname);
             if (count($ldapUrls) > 1) {
                 foreach ($ldapUrls as & $uri) {
+                    if (preg_match('/:\d+$/', $uri) === 0) {
+                        $uri = $uri . ':' . $this->port;
+                    }
                     if (strpos($uri, '://') === false) {
                         $uri = 'ldaps://' . $uri;
                     }
@@ -1192,7 +1195,7 @@ class LdapConnection implements Selectable, Inspectable
 
                 $hostname = implode(' ', $ldapUrls);
             } else {
-                $hostname = 'ldaps://' . $hostname;
+                $hostname = 'ldaps://' . $hostname . ':' . $this->port;
             }
         }