diff --git a/sjrpc/core/connectionmanagers.py b/sjrpc/core/connectionmanagers.py
index 2aeef7c4091a7647257ab6737c1a93ce51d69002..ade66a72cac695da005bf3ac0a5637f11185c895 100644
--- a/sjrpc/core/connectionmanagers.py
+++ b/sjrpc/core/connectionmanagers.py
@@ -177,7 +177,8 @@ class ConnectionManager(object):
         '''
 
         fd = connection.get_fd()
-        self._poll.modify(fd, ConnectionManager.MASK_WRITABLE)
+        if fd is not None:
+            self._poll.modify(fd, ConnectionManager.MASK_WRITABLE)
         
     def nothing_to_write(self, connection):
         '''
@@ -189,7 +190,8 @@ class ConnectionManager(object):
         '''
 
         fd = connection.get_fd()
-        self._poll.modify(fd, ConnectionManager.MASK_NORMAL)
+        if fd is not None:
+            self._poll.modify(fd, ConnectionManager.MASK_NORMAL)
     
     def handle_event(self, fd, event):
         '''
diff --git a/sjrpc/core/rpcconnection.py b/sjrpc/core/rpcconnection.py
index 702ccdfc3ffb402c41d93b8687703038af2538da..02e6c3a1860125d67461444d5fd6c3338b169b2e 100644
--- a/sjrpc/core/rpcconnection.py
+++ b/sjrpc/core/rpcconnection.py
@@ -428,8 +428,10 @@ class RpcConnection(object):
         
         :return: the file descriptor number of the socket
         '''
-        
-        return self._sock.fileno()
+        try:
+            return self._sock.fileno()
+        except socket.error:
+            return None
 
     def getpeername(self):
         '''