Technical Library

E-Mail

Helpful Service Machines

The Basics

Dial up services offer customers a dialup 'on demand' connection to the Internet. For many customers, this means that their connection to the Internet is not always up and running. If your connection is down for any reason, we will guarantee that mail destined for your network does not bounce to the original sender.

What happens if I'm not connected?

When your connection to the Internet is not active, mail destined for users on your network cannot reach you. This mail is stored by us until you reactivate your connection.

Machines that store this mail periodically test for connectivity to your network. When you reactivate your connection, the mail that has been queued for you is sent to your network.

How do I get my mail after I reconnect?

If you do not wish to wait the short period of time needed for our machines to test for connectivity, we offer SMTP-on-Demand service. Using a single finger command, your network informs our backup mail machines that you have re-established connectivity to the Internet. For example:

This command notifies the mx machines that your domain is ready to receive any backed up mail waiting for you. The mail is then sent to your network.

Another option is to use ETRN. This command also allows mail from the backup mail exchangers to be sent to your network.

ETRN, though, will need the following commands for each of the backup exchangers that your email is stored on (mx, mx2, and mx3 or mx4, mx5 and mx6 or mx7, mx8, mx9):

   telnet mx.smtp.psi.net 25
   EHLO smtp.domain.com
   ETRN #domain.com
   250 OK, queue -R 'domain.com' started
   QUIT

Include your mail host after the EHLO command and your domain name after the ETRN command.

How can I specify where I want mail sent?

Many customers chose to have all mail destined for their network sent to one machine called a mail server. This server distributes the mail locally or holds it until users access it to receive their mail. In addition, the mail server gathers all outbound mail and delivers it to the appropriate place.

This does not, necessarily, have to be the case. Some users may wish to have mail sent directly to the machine it is destined for. This is possible as well.

In either instance, our machines need to know where to send inbound mail for your network. This is where Email and Domain Name Service cross. DNS uses records known as MX or mail exchanger records. These records are implemented along with address records to forward mail to the correct place.

How does my mail reach its destination?
Mail Relays

There are almost as many mail packages in existence as there are networks, and not all are as "smart" as others. If you are not running a sendmail-like program, then your mailer is probably not capable of delivering the mail itself. This is true with some SMTP gateways as well.

You will need to use what is known as a Mail Relay or Smart Host which is capable of sending and receiving mail to and from your network. The Mail Relay machines use DNS to translate names into IP addresses.

If your site uses one of our Mail Relay machines, make sure you are using the fully qualified domain name.

Customers who use a Dial Up service and are installing your own mail server must do SMTP mail. What this means is that no matter what type of local mail package you use on your network, you must maintain an SMTP gateway to convert the mail to SMTP format.