want to fetch all email from ISP's server to a local server.
In my current setup, my ISP is providing mail services to us. Means, all my users connect directly to the ISP's server and fetch their emails using outlook. I want to be able to fetch all the email from ISP's server to a linux box inside my network so that my users can fetch their email from our internal linux box instead of connecting to the ISP's server. Basically the purpose is to avoid the limitation of ISP provided mailboxes. For example, users can not have more than 20MBs of email's in their mailboxes etc.
Also, I want that my linux server must store a copy of all the messages for each user. Means, if a user have all the email in the outlook & his machine crashes or anything happens, he should be able to re-gain all his emails from the server again.
Could you guys please suggest the best possible solutions?