diff --git a/letsencrypt-apache/letsencrypt_apache/constants.py b/letsencrypt-apache/letsencrypt_apache/constants.py
index 77f71a461..ab85fb1f6 100644
--- a/letsencrypt-apache/letsencrypt_apache/constants.py
+++ b/letsencrypt-apache/letsencrypt_apache/constants.py
@@ -42,7 +42,7 @@ CLI_DEFAULTS_GENTOO = dict(
     vhost_root="/etc/apache2/vhosts.d",
     vhost_files="*.conf",
     version_cmd=['/usr/sbin/apache2', '-v'],
-    define_cmd=['/usr/sbin/apache2', '-t', '-D', 'DUMP_RUN_CFG'],
+    define_cmd=['apache2ctl', 'virtualhosts'],
     restart_cmd=['apache2ctl', 'graceful'],
     conftest_cmd=['apache2ctl', 'configtest'],
     enmod=None,