diff --git a/pyroute2/ndb/objects/interface.py b/pyroute2/ndb/objects/interface.py
index e270fac3ee5e0d17157db98f8ff91e790e348e6a..681e2e01cd402f27f88c219a7e919e62195c7ae4 100644
--- a/pyroute2/ndb/objects/interface.py
+++ b/pyroute2/ndb/objects/interface.py
@@ -550,7 +550,7 @@ class Interface(RTNL_Object):
     @check_auth('obj:modify')
     def apply(self, rollback=False, fallback=False):
         # translate string link references into numbers
-        for key in ('link', ):
+        for key in ('link', 'master'):
             if key in self and isinstance(self[key], basestring):
                 self[key] = self.ndb.interfaces[self[key]]['index']
         setns = self.state.get() == 'setns'