The GUI seems bit not so attractive. Is there any other email solution that can provide an attractive GUI for clients as well as Administrator. Or Postfix can be changed to have better GUI.
What do you mean by GUI.
POSTFIX is an SMTP server it acts like daemons in UNIX it has no GUI unless you are looking for some front end GUI to control POSTFIX rather than command line.
If you mean clients like MS Outlook and Webmail clients it's totally up to you.
If you are looking for some attractive webmail interface look for mailcube webmail client which supports POP3 , IMAP severs and virtually all SMTP severs.
I don't know of an Exchange-like mail system for UNIX. UNIX has its own way of doing a mailserver which most UNIX mail daemons adhere to pretty strictly, sometimes to the point of using the same or very similar config files.
Actually i have installed web based Postfix-Admin. it has got both Posfix Admin and Postfix users web based interface.
There i can see fetchmail, sendmail options, but as i said the look and feel of the interface (GUI) is not so attractive. So is there any other Web based Mailing options with attractive GUI for both Admin. and Users.
what all (like SMTP server, ??? etc.) need to set for deploying mailing solution on an LAN, so that mails can be sent and received locally,, not on internet.
I am not looking for webmail clients like Outlook, Roundcubes rather a web browser should work for client for using mailing service. Like we do mails exchange on internet via different mail provider websites.
Yes POSTFIX is an SMTP server with some extended features.
If you are looking for some mail solution but it's not free have a look at AXIGEN mail solution.
Just you need to setup postfix properly to send and receive emails either locally or route emails through internet.
I am looking for free mailing solution that i myself can configure and do programming to set up a robust mailing solution.
Is only working with Postfix (i.e. SMTP server) can result in Mailing solution for Intranet and Internet or i need more things to setup like POP3 server, IMAP server etc.
As I said earlier and before in a previous post you need to setup either an IMAP or a POP3 server to allow mail retrieval for users.
SMTP only is not a complete mail solution , You need an IMAP server such Courier-IMAP or a POP3 server such as Dovecot-POP and you might need some database server such as MYSQL and web a server such as Apache to publish some webmail client to allow users to send and view their emails via web browser also you can setup some Anti-Virus / Anti-spam software if needed .
Drop by postfix.org and check their Howtos you will find what you need.
Now you have the required knowledge to setup your mail solution go ahead.