Application Development Software

Hi,
Sorry I am new to this and gradually learning. We are a small company and need to setup a email system. We have a account hosted at godaddy.com.

The problem:

We need to setup email system for internal use as well as for sending emails outside. We do not have servers running all day/night so I didn't want to forward the MX record from GoDaddy to local servers. Moreover we don;t have static IP as well.
Corresponding to our domain say mydomain.com we have setup a local network, mydomain.lan

What I need is to do the following:

Say we have 2 users: user1 and user2. They have local email addresses user1@mydomain.lan and user2@mydomain.lan.
I assume I will need to create user1 and user2@mydomain.com.

1) When user1@mydomain.lan sends a email to user2@mydomain.lan, that goes directly (not a problem).

2) When user1@mydomain.lan sends a email to someone@gmail.com, the email shows up as if coming from user1@mydomain.com (also reply-to is user1@mydomain.com as well if needed)

3) When someone@gmail.com sends a reply to user1@mydomain.com, it is downloaded to user1's inbox.


So far:

a) I have setup the messaging server and i can send user1 -> user2 on local domain.
b) I can send user1 -> someone@gmail.com (no re-write rule written).

I search forums but did not find these questions:

1) How to download emails from mydomain.com to local users.
2) How to redirect so I can do the scenarios described.
3) Is there a better way to set this up than my misrable jumble?


Reading the documentation I have figured out that I need to assign re-write rules and possibly a domain alias in imta.cnf. However I am confused where and if there is documentation to help me do that.

The Sun documentation 819-4428.pdf probably has all what I need. But I have tried and could not live through 1000+ pages of pure technical details. sorry about that....

Could someone please guide me in the right direction?


-Jack