diff --git a/tryton/pysocket.py b/tryton/pysocket.py
index 5b4276d979..04281ab3ba 100644
--- a/tryton/pysocket.py
+++ b/tryton/pysocket.py
@@ -29,6 +29,7 @@ class PySocket:
         self.port = None
         self.ssl = False
         self.ssl_sock = None
+        self.connected = False
 
     def connect(self, host, port=False):
         if not port:
@@ -37,18 +38,17 @@ class PySocket:
         hostname = host
         if host in DNS_CACHE:
             host = DNS_CACHE[host]
-        if not self.sock:
-            self.sock = None
-            if socket.has_ipv6:
-                try:
-                    socket.getaddrinfo(host, int(port), socket.AF_INET6)
-                    self.sock = socket.socket(socket.AF_INET6,
-                            socket.SOCK_STREAM)
-                except:
-                    pass
-            if self.sock is None:
-                self.sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
-            self.sock.settimeout(120)
+        self.sock = None
+        if socket.has_ipv6:
+            try:
+                socket.getaddrinfo(host, int(port), socket.AF_INET6)
+                self.sock = socket.socket(socket.AF_INET6,
+                        socket.SOCK_STREAM)
+            except:
+                pass
+        if self.sock is None:
+            self.sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
+        self.sock.settimeout(120)
         self.sock.connect((host, int(port)))
         DNS_CACHE[hostname], port = self.sock.getpeername()[:2]
         try:
@@ -72,6 +72,7 @@ class PySocket:
         self.host = host
         self.hostname = hostname
         self.port = port
+        self.connected = True
 
     def disconnect(self):
         try:
@@ -95,6 +96,8 @@ class PySocket:
                 self.sock.close()
         except:
             pass
+        self.sock = None
+        self.connected = False
 
     def reconnect(self):
         if self.host and self.port:
diff --git a/tryton/rpc.py b/tryton/rpc.py
index 5829fd74dc..c90d00a3ce 100644
--- a/tryton/rpc.py
+++ b/tryton/rpc.py
@@ -22,9 +22,9 @@ def db_list(host, port):
         try:
             if _SOCK and (_SOCK.hostname != host or _SOCK.port != port):
                 _SOCK.disconnect()
-                _SOCK = None
             if _SOCK is None:
                 _SOCK = pysocket.PySocket()
+            if not _SOCK.connected:
                 _SOCK.connect(host, port)
             try:
                 _SOCK.send(('db', 'list'))
@@ -40,7 +40,6 @@ def db_list(host, port):
             _SEMAPHORE.release()
         return res
     except:
-        _SOCK = None
         return None
 
 def db_exec(host, port, method, *args):
@@ -50,9 +49,9 @@ def db_exec(host, port, method, *args):
         try:
             if _SOCK and (_SOCK.hostname != host or _SOCK.port != port):
                 _SOCK.disconnect()
-                _SOCK = None
             if _SOCK is None:
                 _SOCK= pysocket.PySocket()
+            if not _SOCK.connected:
                 _SOCK.connect(host, port)
             _SOCK.send(('db', method) + args)
             res = _SOCK.receive()
@@ -61,7 +60,6 @@ def db_exec(host, port, method, *args):
             _SEMAPHORE.release()
         return res
     except:
-        _SOCK = None
         raise
 
 def login(username, password, host, port, database):
@@ -73,9 +71,9 @@ def login(username, password, host, port, database):
         try:
             if _SOCK and (_SOCK.hostname != host or _SOCK.port != port):
                 _SOCK.disconnect()
-                _SOCK = None
             if _SOCK is None:
                 _SOCK = pysocket.PySocket()
+            if not _SOCK.connected:
                 _SOCK.connect(host, port)
             _SOCK.send(('common', 'login', database, username, password))
             res = _SOCK.receive()