diff --git a/utils/he_ipv6/ra.py b/utils/he_ipv6/ra.py
index 03b1bf9..e9f14dd 100644
--- a/utils/he_ipv6/ra.py
+++ b/utils/he_ipv6/ra.py
@@ -31,7 +31,7 @@ class RAConf(object):
     def ext_init(self):
         self.tpl_dir = os.path.abspath(os.path.expanduser(self.tpl_dir))
         self.loader = jinja2.FileSystemLoader(self.tpl_dir)
-        self.tpl_env = jinja2.Environment(loader = self.loader)
+        self.tpl_env = jinja2.Environment(loader = self.loader, extensions = ['jinja2.ext.do'])
         self.tpl = self.tpl_env.get_template(self.tpl_name)
         return(None)