[OpenIndiana-discuss] IMAP namespace... what on earth is that, really? In a deeper sense, I mean.

[Hans J. Albertsson]

In all the cases so far where I have had to set up IMAP servers on Sun 
things (which is at least 5 years ago) I never had occasion to think 
about what is actually meant by the notion of "namespace".

Now, setting up dovecot, I realise I really need to UNDERSTAND in a 
deeper sense what the "namespace" concept is, for mail systems.

I have always had the idea, accompanied by a slightly uneasy feeling, 
that it might just as well be replaced by "notional mailbox naming 
system and convention", and that it intends to capture how to deal with 
mailbox naming conventions in the face of conflicting needs.

But I am not sure.

I have looked at RFC2060, and RFC2342, and the nearest thing to a 
definition I have found is 5.1.2 in 2060 and various sections in 2342. 
All is implicit, and not in the form of a dictionary definition.

My current guess is that a namespace is a set of names made available to 
the user by the mail presentation service his MUA uses.
The intent of the set of names is to enable a user and his MUA to 
disambiguate between mailboxes accessed from different sources, such as 
shared mailboxes, the user's private mailboxes, and any mailboxes 
belonging to users that have configured in an intent for such a mailbox 
to be made accessible to the current user.

I suppose that is all (at least nearly) true, but is there anything more 
to the notion of IMAP namespaces, that I have missed?