standard murder configuration problem [SOLVED]

[Maurizio Lo Bosco]

the problem seams to be related to the 

plain authentication disabled without the TLS as reported in 
http://www.irbs.net/internet/info-cyrus/0401/0578.html
activating the tls paramenters in imapd.conf on frontend and backend 
everything works fine.
Kind regards
  Maurizio

> I'm going crazy configuring a standard murder architecture with 3 different
> servers
>  1 frontend (mx1)
>  1 mupdate master (mupdate)
>  1 backend (ariel)
> the OS is debian etch.
> the imap/pop3 and lmtp connections are not working from the frontend to the
> backend