I am requested to move a domain with email service which is currently hosted in an ISP to the company server. The requirement is to make the transfer transparent to existing email users. I've set up Sendmail and Squirrelmail to provide the service.
I am new to Linux and Sendmail. The only way I know to create a mail account is to create a user in the Linux system (Fedora 5 in my case). The problem is that the existing ISP use full email addresses as user logins for the email accounts (i.e. users enter "email@example.com" instead of "user" in Outlook Express's user ID field). I tried to create a user in the "firstname.lastname@example.org" format but fail.
Must a Sendmail user be a system user and have the same user name and password? How can I set up the system to use email address as user name?
You're going to run in to another problem. Sendmail is an MTA.. it's just used to sendmail from one system to another. It is not used to receive email. For instance, when you're users enter "email@example.com" in to Outlook Express, this is to connect to a POP3 (or perhaps IMAP) server, not an SMTP server (Sendmail is for SMTP). So you still need another application for that. Luckily, most Linux distros come with a POP3 server. However, SquirrelMail is an IMAP client, so you'd need an IMAP server.
If you want to use full email addresses, then you can't use system users, because system users can't include the domain, just the username. You'll need to authenticate against something else. My favorite setup is Postfix+Courier+MySQL. Postfix (instead of Sendmail), because it's much easier to configure for doing what you're wanting to do. Courier as both an IMAP and POP3 server, so you (or your users, if you'd like) have a choice. And MySQL, to hold the usernames in the form of "firstname.lastname@example.org". Search for a Postfix Courier MySQL HOWTO to get detailed step-by-step instructions.
Thank you for your reply. I've tried to install Postfix and cannot make it works. Anyway, I will check out authentication using Sendmail+MySQL as I also have MySQL up and running. In Addition, I google around and find some messages talking about sasl authentication. May I use it to do what I want and how to do it?
You would use SASL authentication if you wanted people to be able to send email using your server from anywhere and require a username and password them do so. This still doesn't relate to them being able to receive their email though.