1 files changed, 4 insertions, 2 deletions
diff --git a/lib/net/imap.rb b/lib/net/imap.rb
index f8c0d3be4c..6162ffa0d0 100644
--- a/lib/net/imap.rb
+++ b/lib/net/imap.rb
@@ -284,9 +284,11 @@ module Net
 
     # Disconnects from the server.
     def disconnect
-      if SSL::SSLSocket === @sock
+      begin
+        # try to call SSL::SSLSocket#io.
         @sock.io.shutdown
-      else
+      rescue NoMethodError
+        # @sock is not an SSL::SSLSocket.
         @sock.shutdown
       end
       @receiver_thread.join