System information
135Chapter 9 Customizing Services
If you want to allow access to mail service on the Internet and you have a cable router,
DSL router, or other network router, your router must have port forwarding (port
mapping) congured for mail service. For more information, see “Protecting a Small
Network” on page 35.
If you want to allow access to mail service outside your local network and your local
network has a separate rewall device, ask the rewall administrator to open the
rewall for the ports that mail service uses. For a list of ports, see “Services and Ports” on
page 175.
Specifying a Mail Relay Server
Your mail service can relay outgoing mail through another server, and that relay server
will forward the mail to its destination.
If you use a commercial Internet service provider (ISP), it may stipulate that all Â
outgoing email be relayed through a designated server.
If your organization provides your Internet service, your server may need to use a Â
relay server to deliver outgoing mail through a rewall. In this case, your organization
will designate a particular server for relaying mail through the rewall.
You need to use a relay server if the DNS service for your ISP or organization can’t Â
resolve the public IP address of your server (or your AirPort Base Station or other
router) to your server’s DNS name; this is called a reverse lookup.
Important: Use a relay server only if your ISP or organization requires one. Relaying
mail through another server without permission may make your server appear to be a
mail service abuser.