my email settings in server-manager are all set to allow public and private access.
by default the public access to imap is via imaps, on port 993.
to allow public access to pop or imap (as opposed to pops and imaps) use the following commands:
config setprop imap access public
signal-event email-update
this will then allow the option to be available in the server-manager.
my personal opinion is it is better to work with the imaps and its increased security than to open imap to the world. the sme gurus (bless them!) must agree because from version 7 imap and pop3 public access has been disabled by default.
cheers,
shell