Setting Up an SMTP Filter

You can set up a Simple Mail Transfer Protocol (SMTP) exception on the server's public interface to allow SMTP mail servers or SMTP gateways in your private network to send and receive mail through the Novell BorderManager 3.8 firewall.

This section contains the following topics:


Setting Up a Stateful SMTP Filter

  1. Select Configure TCP/IP Filters, click Packet Forwarding Filters, then click Exceptions.

  2. Press Ins to define a new exception.

  3. If you want private SMTP servers or gateways to be able to send mail through the firewall, specify the server's private interface as the Source Interface.

    or

    If you want public SMTP servers to be able to send mail to the SMTP server in your private network, and you have not enabled the Mail proxy, specify the server's public interface as the Source Interface.

  4. If you want private SMTP servers or gateways to be able to send mail through the firewall, specify the server's public interface as the Destination Interface.

    or

    If you want public SMTP servers to be able to send mail to the SMTP server in your private network, and you have not enabled the Mail proxy, specify the server's private interface as the Destination Interface.

  5. Press Enter for Packet Type, then select smtp-st.

  6. Press Enter, then select Yes to save the filter.

    IMPORTANT:  The outbound stateful SMTP filter does not allow domain names to be resolved by a DNS server on the public network.


Setting Up Static Filters for SMTP

If you do not want to configure a stateful SMTP exception, you can create static filters instead. Simply create a static SMTP filter exception in both the inbound and outbound directions. Make sure you enable ACK bit filtering for the exception in the inbound direction.

IMPORTANT:  These filters do not forward requests for domain name resolution. A DNS filter is required.