The Microsoft exchange server , is a mail server, which organizations uses to enable the company to use e-mails across their network and of course send and receive e-mails outside with other clients, other organizations.

The exchange server includes filtering mechanisms (blocking e-mail flooding, sender’s address, connection filtering using DNS RBL lists (Which is a list of banned blacklisted domains), use a mail domain (so the organization will be using a unique mail server that is their own) , also the Microsoft exchange server included features like: 16 TB (Tera-Byte) of database size (to hold all of the e-mails), Scripting language to maintain the exchange server, 64 Bit performance and scalability, including a more user friendly GUI, calendaring including calendar sharing (between employees) so you can see who is available/busy at the time you want to set the meeting, and enable you to set the meeting when everyone are available), It has a web access (so you can manage it from outside/within the organization.

You would be able to set the configuration of the mail users, in groups and set who can use what, what can the user do with his mailbox, where is it stored, how large his
capacity is etc… like the Microsoft Active-Directory, the Microsoft exchange server had good user configuration and maintenance capabilities, so you could configure and maintain the Microsoft exchange server. The Microsoft exchange server also includes anti-spam, anti-virus protection, clustering for performance.

The Microsoft Exchange system, requires licensing, which is not the same as the Microsoft CAL licenses, the Exchange licenses are for defining how many users can be used on the Microsoft Exchange system, how many mail boxes can you use.

Microsoft Exchange server can be used from mobiles as well as regular mail clients, the mechanism called Active-Sync that was added to the exchange server 2003, enabled mobile connection.

The main advantage of the Microsoft exchange server is the sharing of calendars which is very important for large scaled companies, for setting meetings, and tracking who is available when.
Enjoy.