This wizard will help you configure your internal and outgoing mail. When configured, this SMTP server will allow users of your local network to send internal and external mail through it. Likewise, if your server is referenced on the Internet public DNS as a MX server for your domain name, then it will also receive and manage mail from the Internet addressed to users of your domain. In this case, make sure you open the corresponding ports in your firewall.
The first step consists of choosing whether you will use an external SMTP relay or not. If you can use one provided by your ISP then choose External mail server in the drop-down list. Otherwise, choose Internal mail server.
If you chose External mail server, the following steps will be displayed:
Outgoing mail address
Address masquerading is a method to hide all hosts inside a domain behind their mail gateway, and to make it appear as if the mail comes from the gateway itself, instead of from individual machines.
Type the domain name from which outgoing mail will appear to come from. For example, if user queen sends an e-mail from machine moon.pingus.org to someone else on the Internet and you chose pingus.org as Masquerade domain name, then the e-mail will appear to come from queen@pingus.org
Internet Mail Gateway
This is where you define the mail server of the ISP responsible for relaying your outgoing messages.
myorigin
Type the domain name from which local mail will appear to come from. For example, if you chose pingus.org as the myorigin parameter, warning messages from the mail server will appear to come from postfix@pingus.org. The default value is $myhostname which is the server's FQDN host name.
If you chose Internal mail server on the first step, you will only have to fill the myorigin parameter.