Hi friends,
I have installed postfix in Ubuntu 8.10. I can send emails to local users and also to users outside my network. I have used smtp.gmail.com as relay host. currently I am able to send email trough evolution where my evolution account smtp is configured as 127.0.0.1. but I am not able to configure it as my IP address (192.168.1.27).
can any one please help me out

Try this -

By default postfix will only listen on the loopback interface, the change above will configure postfix to listen on all network interfaces

cheers

Now I am able to send emails configuring my IP address in evolution but I am not able to send emails from evolution configured from other machine.

eg. I have an Ubuntu machine named ubuntu which I am using to run Postfix server. It has the IP as 192.168.1.104. I have configured evolution using the IP address of same server as smtp server (192.168.1.104). emails are sent through evolution very smoothly. but when I move on to the other host which is named trinity (192.168.1.100) and try to give the same IP address (192.168.1.104) as smtp server IP in Local network I am not able to send emails. My evolution says connection to the server was refused. Is it some security issue though I have the firewall disabled on both the machines.

You'll need to tell postfix which networks to relay for:

..where 192.168.1.0/24 is your lan

cheers