Re: [EXIM] Case of local parts

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Author: Exim Users Mailing List
Date:  
To: Exim Users Mailing List
Subject: Re: [EXIM] Case of local parts
[ On Wednesday, February 24, 1999 at 15:41:08 (-0500), Bruce Bowler wrote: ]
> Subject: Re: [EXIM] Case of local parts
>
> Actually, thinking about it, Chad's solution doesn't help my problem at
> all. The only way to solve my particular problem is with a serial read
> through the passwd file looking caselessly at the usernames.


The problem here is, as Philip almost clearly stated, is that a serial
read through the "passwd file" is not possible in a growing number of
circumstances. For example I'm soon to deploy an LDAP server as the
"passwd file" for a POP/IMAP mail server for a client with potentially
tens of thousands of lusers and there'll be no way to do a sequential
scan (not that you'd want to!) in that scenario even if it were
acceptable from a performance perspective.

There's a simple rule that I apply to all systems running any mailer
that I've ever been involved with (well, at least since I came up with
the idea -- before that it was still chaos in my mind).

If you have any local lusers with uppercase names then you should
implement fully case-sensitive mailbox local parts -- lusers beware or
they don't get their e-mail.

However if you can enforce a policy of all lower-case user-names then
you make the mailer lower-case the mailbox local part before doing
anything with it. Note that this scenario totally avoids the issue of
case-less string comparisons with the "passwd file" in the first place.

Any in-between scenario will lend itself to potential collisions and
should be avoided at all cost. This is of course because Unix user
names are case-sensitive.

-- 
                            Greg A. Woods


+1 416 218-0098      VE3TCP      <gwoods@???>      <robohack!woods>
Planix, Inc. <woods@???>; Secrets of the Weird <woods@???>


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