Index: lisp/imap.el
===================================================================
RCS file: /usr/local/cvsroot/gnus/lisp/imap.el,v
retrieving revision 7.29
diff -u -r7.29 imap.el
--- lisp/imap.el	26 Jun 2006 12:08:33 -0000	7.29
+++ lisp/imap.el	4 Sep 2006 17:45:39 -0000
@@ -1142,7 +1142,16 @@
        (buffer-live-p buffer)
        (with-current-buffer buffer
 	 (and imap-process
-	      (memq (process-status imap-process) '(open run))))))
+	      (memq (process-status imap-process) '(open run))
+	      (imap-ping-server)))))
+
+(defun imap-ping-server (&optional buffer)
+  "Ping the imap server in BUFFER with a noop command. Return non-nil
+if the server responds, and nil if it does not respond. If BUFFER is
+nil, the current buffer is used."
+  (condition-case ()
+      (imap-ok-p (imap-send-command-wait "NOOP" buffer))
+    (error nil)))
 
 (defun imap-authenticate (&optional user passwd buffer)
   "Authenticate to server in BUFFER, using current buffer if nil.