## Configuring Mail Services

Your control panel works in cooperation with Qmail mail server, which provides mail services for your domains. After installation the mail server is configured automatically and is ready to serve, however, we recommend that you review the default settings to make sure that they satisfy your needs:

1. Click the Server shortcut in the navigation pane.
2. Click the Mail icon in the Services group. The server-wide mail preferences screen will open on the Preferences tab.
3. If you wish to limit the size of an e-mail message that can be sent through your server, type the desired value in kilobytes into the Maximum letter size box, otherwise, leave this field blank.
4. Select the mail relay mode.

   With closed relay the mail server will accept only e-mail addressed to the users who have mailboxes on this server. Your customers will not be able to send any mail through your outgoing SMTP server, therefore, we do not recommend closing mail relay.

   With relay after authorization, only your customers will be able to receive and send e-mail through your mail server. We recommend that you leave the authorization is required option selected, and specify allowed authentication methods:

   - POP3 authorization. With POP3 authorization, once a user has successfully authenticated to the POP server, he or she is permitted to receive and send e-mail through the mail server for the next 20 minutes (default value). You can adjust this interval by specifying another value in the lock time box.
   - SMTP authorization. With SMTP authorization, your mail server requires authorization if the e-mail message must be sent to an external address. Your mail server supports LOGIN, CRAM-MD5 and PLAIN methods of SMTP authorization.
5. If you wish to protect your users from dictionary attacks by not allowing them to use simple passwords, select the Check the passwords for mailboxes in the dictionary option.

   A dictionary attack is when someone tries to find out a valid user name and password by running a program that tries different combinations of dictionary words in different languages. Dictionary attacks can be successful because many users choose their passwords carelessly.

6. Select the mail account name format.

   Selecting the Use of short and full names is allowed option will allow users to log in to their mail accounts by specifying only the left part of e-mail address before the @ sign (e.g. username), or by specifying the full e-mail address (e.g. username@your-domain.com).

   To avoid possible authorization problems for e-mail users who reside in different domains but have identical user names and passwords, we recommend that you choose the Only use of full mail account names is allowed option.

   Once you have set your mail server to support only full mail account names, you will not be able to switch back to supporting short account names until you make sure there are no encrypted passwords for mailboxes and user accounts with coinciding user names and passwords residing in different domains.

7. Click OK to submit any changes.

   Note: If you wish to set up anti-spam systems, such as SpamAssassin spam filter, or protection systems based on DNS blackhole lists or Sender Policy Framework (SPF), proceed to the Setting Up Anti-Spam Protection section.

In this section: Setting Up Anti-Spam Protection Configuring Antivirus Configuring Mailman Mailing List Software