diff --git a/lib/os/class.ISPConfigDebianOS.inc.php b/lib/os/class.ISPConfigDebianOS.inc.php
index 309971d27cbb89ca0ccfaa9955f4b7a500590496..b4f29b0463a632dd028541d05f33dab0f1b7260f 100644
--- a/lib/os/class.ISPConfigDebianOS.inc.php
+++ b/lib/os/class.ISPConfigDebianOS.inc.php
@@ -1594,6 +1594,12 @@ mailman-unsubscribe:  "|/var/lib/mailman/mail/mailman unsubscribe mailman"';
 			} elseif(strpos($result, '127.0.0.1') === false) {
 				ISPConfigLog::warn('Unexpected resolver response: ' . $result, true);
 			}
+		} else {
+			$cmd = 'resolvconf -u 2>&1';
+			$result = $this->exec($cmd);
+			if($result === false) {
+				throw new ISPConfigOSException('Command ' . $cmd . ' failed.');
+			}
 		}
 
 		if(ISPConfig::shallInstall('web')) {