Re: [Exim] A bit OT - apologies in advance!

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Author: Konrad Michels
Date:  
To: Nigel Metheringham
CC: exim-users
Subject: Re: [Exim] A bit OT - apologies in advance!
Thanks a ton Nigel. I'll be chasing that down a bit - don't know if
I'll have any luck tho . . .

Later
Konrad


On Wed, 2003-07-16 at 16:34, Nigel Metheringham wrote:
> On Tue, 2003-07-15 at 15:49, Konrad Michels wrote:
> > However, my client has a requirement for pop3 access for lusers to get
> > their mail, and worse still he wants people to be able to share a
> > mailbox, similar to the way BT and Demon do mailbox sharing: ie you
> > login with you entire e-mail address as the user name, using a common
> > password. The user then sees only the mail addressed to them, despite
> > the fact that in reality those mails are mixed in amongst dozens of
> > other people's mails. There is one admin user per mailbox who can read
> > everyone's mail.
>
> Its interesting to watch people screaming about this one... I have
> actually done it myself for a specific type of application.
>
> Freeserve, and other free ISPs in the UK, gave out a domain per customer
> - say customername.freeserve.co.uk. They used
> customername.freeserve.co.uk as their login name (with a password they
> specified at signup time, and all mail to any local part
> @customername.freeserve.co.uk went into a single mailbox. For the
> clueful there were envelope-to: headers to allow you to split mailboxes
> into different local parts.
>
> However we added another wrinkle to it - based on an idea used
> previously by Demon, but enhanced somewhat by us.
>
> If you set your pop username to be fred@???
> then the pop daemon filtered the view of the mailbox so you only saw
> mail delivered to local part "fred".
>
> There were some other wrinkles - you could actually put a form of
> expression - including negatives - in the selector, so you could look
> separately for messages addressed to fred, jim & bob and then select all
> messages for any local parts *other* than red, jim or bob.
>
> The implementation was handled in 3 parts.
>
> First, when exim delivered mail (into a Maildir) it used the maildir tag
> functionality to add a lowercased local part to the file name.
>
> Second, the qmail pop user part (which handled authentication only - the
> real popper is forked off after authentication) added an environment
> variable with anything before an @ or : in the username, and only used
> the later part for the authentication.
>
> Third the qmail pop handler had some code in that parsed the selector
> string and modified the directory scan to select or ignore stuff
> appropriately.
>
> The down side is I did not release that code whilst at Planet/Energis,
> and I have no idea if you have any chance of obtaining code from them.
> Frankly replicating that work would not take long - the original took me
> under a day of hacking. Working out a suitable selector syntax was the
> most difficult part. See if Demon still document this stuff.
>
> I can't find my old postings on it - only a posting refering to it:-
> http://groups.google.com/groups?hl=en&lr=&ie=UTF-8&oe=utf-8&selm=MPG.18646d1dd70b60eb98995f%40news.freeserve.net
>
>
>     Nigel.

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