There are some commands that my IMAP server is not going to support, for instance LSUB; this is either because they don't make sense in my specific application, or because of schedule constraints. What is the correct answer to send clients that send commands I don't support?
You MUST support ALL commands that are in the base specification.
In certain cases, you may limit the functionality of your server. For example, if you do not have non-INBOX mailboxes, you can respond NO to any CREATE, DELETE, or RENAME command; and respond NO to any attempt to SUBSCRIBE, COPY, or APPEND with a name other than INBOX.
But you do not have the option of not implementing a command entirely.
-- Mark --
http://staff.washington.edu/mrc Science does not emerge from voting, party politics, or public debate. Si vis pacem, para bellum.
