# Cyrus IMAP Server: Special Characters

This document is supposed to be a repository of "special characters" used in Cyrus naming of users, folders, directory paths, etc.

## Current Uses

Character: +

- (LMTP) Separation of postuser and target mailbox for delivery

- (LMTP) Separation of username and submailbox for delivery

- (IMAP) Flag at end of login name that indicates that LIST should return LSUB results (when imapmagicplus is set)

- (POP3) POP a subfolder directly (e.g. rjs3+foo POPs user.rjs3.foo)

Character: . /

- [mailbox names] Hierarchy separators

Character: ^

- [mailbox names] In unixhierarchysep, ^ is the part of the internal name that represents a '.'

Characters: @ %

- [usernames] These are realm separators for the purposes of authentication

## Future Uses

Character: +

- IMAP LIST filters (e.g. rjs3+foo will only list folders that match foo*)

- possibly other interpretations here: - rjs3+foo will do an effective chroot(foo.) - rjs3+foo will only list folders in user.rjs3.foo*