30.3  Dial-up Line + ETRN

Information and Requirements

  1. The company uses the domain thirdcompany.com and the primary MX record points to the computer where Kerio MailServer is installed (its DNS name is mail.thirdcompany.com).

  2. The secondary MX record is directed to the SMTP server.

    etrn.isp.com,

    which supports the ETRN command and requires authentication by username and password.

  3. The computer is connected to the Internet via a dial-up line (a static IP is assigned, to which the DNS name mail.thirdcompany.com is assigned).

  4. The ISP enables sending outgoing email via their server

    smtp.isp.com,

    if the user authenticates by username and password.

  5. During working hours (Mon-Fri 8:00-17:00) mail will be downloaded every hour and after working hours at 20:00, 0:00 and 5:00

Implementation

  1. In the Configuration → Domains section, create the primary local domain thirdcompany.com and enter the DNS name of the server mail.thirdcompany.com. When the line is up Kerio MailServer will function as the primary server for this domain. While the line is down email will be sent to a secondary server.

  2. In the Domain Settings → Users section, create user accounts for all local users.

  3. The server will connect to the Internet using a dial-up connection (that already exists in the system). In the Configuration → Internet Connection section, select Offline and tick Use RAS to connect to the Internet. Choose the requested dial-up connection and fill in the appropriate username and password.

  4. All outgoing mail will be sent to a relay SMTP server. On the SMTP Delivery tab in the Configuration → SMTP server section, select Use relay SMTP server and enter its name — smtp.isp.com. The server requires authentication — enable the option Relay server requires authentication and fill in the appropriate username and password. Set the authentication type to SMTP AUTH Command.

  5. Under Configuration → ETRN Download, define the following information:

    server: etrn.isp.com,

    domain: thethirdparty.com,

    Server requires authentication, enter username and password.

  6. In the Configuration/Definitions/Time Ranges section, create a time interval Working hours, containing the range 8:00:00-17:00:00 valid from Monday through Friday, to be used in scheduling.

  7. Set up scheduling for sending and downloading of messages. Add scheduling for every hour (Every 1:00) valid at the time interval Working hours and three schedulings for certain times (At) that will be valid all the time. For all schedulings tick the On-demand mail relay option (i.e. receiving mail using ETRN) but also Send mail in mail queue.