Re: mail.local NSS awareness

["Greg A. Woods; Planix, Inc." <woods%planix.ca@localhost>]

On 30-Apr-08, at 8:14 AM, I wrote:
> Indeed mail.local _could_ be made so blind as to just create a file  
> in the spool directory with the same name as the user-id (though  
> there could be issues with character case, depending on what the MTA  
> passes to it).  In fact I would strongly prefer it to be that way.


I want to point out that I am very well aware there is the issue of  
changing the ownership of the mail spool file.  There have been other  
solutions to this problem in the past (i.e. such that the spool file  
does not have to be owned by the user and thus also such that the LDA  
doesn't have to run as root, and all the while not compromising  
privacy, at least not so long as the MUAs are securely coded too).

However I agree that to keep the current spool interface the LDA  
_must_ return a "temporary" error indication to the MTA so that the  
message can remain in the local spool until such time that the LDA can  
verify the username and learn what the user-ID is.  Given the  
requirement to maintain a Sendmail-compatible LDA interface this means  
the only acceptable exit code for this situation would be EX_TEMPFAIL.

I don't have YP compiled into any of my currently running systems so I  
can't test getpwnam() and getpwnam_r().

Note also that any proper MTA will never lose mail if the LDA returns  
a non-zero and non-temporary exit code -- a bounce message will be  
formulated and the message will be returned to the sender (and if that  
fails the message will be sent to the local postmaster).

--
                                        Greg A. Woods; Planix, Inc.
                                        <woods%planix.ca@localhost>