I have set up a virtual mail server and need to know what else i can do to make sure that it is functioning the proper way. I use Redhat Linux 4.0ES. I currently have 2 business customers on the box. I do the following to set up mail.
1. Set up the DNS on my name servers (I know that is correct) Pointed the domian to my name servers.
On the mail server itself
1. I edit /etc/hosts (add mail.customer.com and associate that with the IP I have assigned.)
2. apply the ip address to the /etc/sysconfig/network-scripts directory (ifcfg-eth0:4) and bring the interface up.
3. Edit /etc/mail/sendmail.mc ( I add the Cwcustomer.com line) and compile; make -C /etc/mail
4. add mail.customer.com to /etc/mail/local-host-names
5. add the usernames and passwords /usr/sbin/useradd -c "Name" name
6. modify the users /use/sbin/usermod -s /bin/false
My issue is this. How can i group the customers by company such that if two or more of the companies want to use HR@company.com, for example, (use the username HR), they will be exclusive of one another?