1 files changed, 12 insertions, 0 deletions
diff --git a/server.go b/server.go
index 267f6ad..a59c0e4 100644
--- a/server.go
+++ b/server.go
@@ -127,6 +127,12 @@ func (s *Server) parseIMAPUpstream() error {
 		panic("unreachable")
 	}
 
+	c, err := s.dialIMAP()
+	if err != nil {
+		return fmt.Errorf("failed to connect to IMAP server: %v", err)
+	}
+	c.Close()
+
 	s.e.Logger.Printf("Configured upstream IMAP server: %v", u)
 	return nil
 }
@@ -159,6 +165,12 @@ func (s *Server) parseSMTPUpstream() error {
 		panic("unreachable")
 	}
 
+	c, err := s.dialSMTP()
+	if err != nil {
+		return fmt.Errorf("failed to connect to SMTP server: %v", err)
+	}
+	c.Close()
+
 	s.e.Logger.Printf("Configured upstream SMTP server: %v", u)
 	return nil
 }