want to setup users always use their own domainname sending emails

Hello everyone,



I have DA build 1.2 on a Centos 6.3 OS.

For example the servername is server.mydomain.com and one of the users have a domain called userdomain.com



1)All the users that send email from PHP scripts (using the PHP mail() function) have the problem that the receiver of the email gets an senders adress like username@server.mydomain.com. I wish this to change to the user domain for example username@userdomain.com.



2) Users that sends email from roundcube have username@localhost as sender by default. It is easy to change for the user but i like to have it automaticly setup to username@userdomain.com.



Any help would be great.



Thanks in advance,



Frank.

want to setup users always use their own domainname sending emails