How to allow access to the mail server by individual domains - Sendmail

The access database (normally in /etc/mail/access) allows a mail administrator to administratively allow access to the mail server by individual domains. Each database entry consists of a domain name or network number as the key and an action as the value.Keys can be a fully or partly qualified host or domain name such as host.subdomain.domain.com, subdomain.domain.com, or domain.com. The last