> 
>    3) Set yout MTA's and MUA's to 2555, uid bin, gid mail. (sendmail,
>    mailx, binmail, etc.)
> 
> 
> this is where this idea totally falls down for me.  you think i'm
> going to trust all these programs with gid mail?
> 
> the concept of a single directory for multiple users' mail spools
> _has_ to be given up before you can even dream of having a safe
> and secure local mail delivery system.
"Safe and Secure" is a misnomer with Unix mail under any flavor. 
Mail is transmitted in cleartext across the internet.  How much 
privacy do you think there is _anywhere_ in the process?
The original problem was to handle the permissions problems on the 
mail spool directory.  I believe the thread has lost sight of that, 
and become directed at redesigning the mail process, which is 
well beyond the scope of this thread.

>