Use 'sendmail-send-it' for 'send-mail-function' under Debian as
'smtpmail-send-it' freeze with Emacs 23.3.1.
--- a/.emacs-my Mon Dec 12 23:04:55 2011 +0200
+++ b/.emacs-my Thu Dec 15 22:16:25 2011 +0200
@@ -1247,7 +1247,7 @@
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
(message "smtp, smtpmail")
-(when (boundp 'smtpmail-smtp-server)
+(when (and (not (eq system-type 'gnu/linux)) (boundp 'smtpmail-smtp-server))
(require 'smtpmail)
(setq
;; If you use the default mail user agent.