I  use another ISP . I can send mail to Quadnet email addresses but can't send mail to other users of the Internet. What is wrong?

Mail Relaying is defined as connecting to the internet though one ISP and sending mail through another ISP. This is not allowed by Quadnet.

Anti-Mail relaying needs to be invoked at Quadnet due to the large amounts of Spam flowing through mail servers.  Spam is unsolicited mail sent to a number of e-mail addresses, usually to solicit business. It is not only annoying or offensive but can also be harmful to the e-mail system by flooding the mail queue of the mail server or of an individual user. By using a mail relay, a spammer tries to hide the true source of the spam. By spoofing (using a false or fake e-mail address), the spammer hides the true e-mail address from which the spam was sent.

A greater problem is mail relaying which results in Quadnet e-mail users being unable to communicate with certain Internet users. Mail servers at some organizations will not accept mail from any mail server which allows mail relaying. Lists such as the Open Relay Blocking System (ORBS) list and the Mail Abuse Protection System (MAPS) Realtime Blackhole List (RBL) identify servers which allow relaying.

Resolution:

    To use our mail server, please reconnect to the Quadnet mail server or,
    Configure the SMTP server in your email program to the ISP you are connected to.

The SMTP server can be changed as follows:

    In Netscape 2.0.2 or 3.0.x, select the Options menu, select Mail and News Preferences, and click on the Server tab in the window that appears.
 
    In Netscape Communicator 4.0, select the Edit menu, select Preferences, click on Mail & Groups from the list on the left side, and on click on Mail Server.
 
    In Eudora Light 3.x, select the Special menu, select Settings, and click on the Host icon from the list on the left side.