diff --git a/Lib/imaplib.py b/Lib/imaplib.py
index 9c38e1c823d..8c14728193d 100644
--- a/Lib/imaplib.py
+++ b/Lib/imaplib.py
@@ -169,6 +169,17 @@ class IMAP4:
 
         self.open(host, port)
 
+        try:
+            self._connect()
+        except Exception:
+            try:
+                self.shutdown()
+            except socket.error:
+                pass
+            raise
+
+
+    def _connect(self):
         # Create unique tag for this session,
         # and compile tagged response matcher.