Re: The IMAP APPENDLIMIT Extension

Jay,

I have not said anything on APPENDLIMIT before but, reading your 
latest draft now, there are a few things I wonder about.  I don't 
think any of these necessarily requires any changes to the draft but 
some may merit additional consideration.

In section 5 you make reference to "the server's fixed maximum mail 
upload size".  What is the intended scope of said fixedness.  Should 
a client assume that a maximum upload size obtained in one session 
applies in a later session?  I think it should not.  Hardware or 
other changes at the server could surely lead to a maximum upload 
size changing over time.

How should a client behave if it obtains a maximum upload size for a 
given mailbox in a LIST command and then later in the same session it 
does a SELECT/EXAMINE for the same mailbox that quotes a different 
maximum upload size?  For that matter, is it valid for a server to 
return different maximum upload sizes in CAPABILITY responses within 
a single session?  In cases where a maximum upload size is dependent 
on a quota, it could make sense for these things to happen.

Surely it would be very valuable to include in this extension a means 
for a server to indicate that it does not accept APPENDs at all.  For 
IMAP servers fronting email archives, it is entirely reasonable for 
APPENDs to be unsupported.  In other cases, it seems reasonable for 
APPENDs to be disallowed for certain mailboxes (as, for example, in a 
proxy situation or when a mailbox reaches maximum capacity).  An easy 
way to deal with this would perhaps be to change the syntax to allow 
an append limit of 0 with the meaning, not that zero-length messages 
may be APPENDed (something that my checks show that many servers 
disallow anyway), but that APPENDs are not allowed period.  This 
could avoid a lot of trouble, I believe.

Pete Maclean

At 05:12 PM 12/19/2014, Jayantheesh S B wrote:
>Hi All,
>
>Please find the next version of the draft attached with all the 
>review comments addressed.
>
>If you have any comments/suggestions in the attached version, kindly share it.
>
>Regards,
>Jay
>
>_______________________________________________
>imapext mailing list
>[email protected]
>https://www.ietf.org/mailman/listinfo/imapext

_______________________________________________
imapext mailing list
[email protected]
https://www.ietf.org/mailman/listinfo/imapext