1 - what are your other trusted source addresses? if it's still local on a different subnet or something, then just expand the my_networks options, e.g. from 192.168.1.0/24 to 192.168.0.0/16. if it's unknown remote locations, possibly dynamic, then you'd probably want to look at smtp authentication.
2 - dovecot. no idea about calendars though, clearly a mail protocol daemon should never have anything to do with calendars at all.
3 - to directly remove it, just delete the directory on the web server. there may be package management around that but i assume there isn't otherwise you'd have mentioned it.
squirrelmail is very easy to install, esp with postfix / dovecot. there are many many docs about via google. it is a pretty duff webmail solution though... horde/imp is *MUCH* *MUCH* better, but harder to get fully working.
Last edited by acid_kewpie; 12-26-2007 at 08:37 AM.