diff --git a/tryton/pysocket.py b/tryton/pysocket.py
index 89ecbc41c5..77112e48ea 100644
--- a/tryton/pysocket.py
+++ b/tryton/pysocket.py
@@ -35,6 +35,7 @@ class PySocket:
     def __init__(self, sock=None):
         self.sock = sock
         self.host = None
+        self.hostname = None
         self.port = None
         self.ssl = False
         self.ssl_sock = None