diff --git a/frn/protocol/server.py b/frn/protocol/server.py
index 1e599e5..ff79957 100644
--- a/frn/protocol/server.py
+++ b/frn/protocol/server.py
@@ -119,6 +119,8 @@ class FRNServer(BufferingLineReceiver, TimeoutMixin):
             self.sendLine(str(versions.client))
             self.factory.serverAuth.update(MT='', SV=versions.server,
                 AL=self.role, KP=self.kp)
+            if self.role == 'DUPL':
+                self.factory.serverAuth.AL = 'BLOCK' # TODO: verify other results
             self.sendLine(
                 self.factory.serverAuth.asXML('MT','SV','AL','BN','BP','KP'))
             if self.role not in ['OK', 'OWNER', 'ADMIN']: