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 3.7 firewall.

This section contains:

• Setting Up a Stateful SMTP Filter
• Setting Up Static Filters for SMTP

Setting Up a Stateful SMTP Filter

To set up a stateful SMTP filter exception,

1. Select Configure TCP/IP Filters > Packet Forwarding Filters > Exceptions.

2. Press Ins to define a new exception.

3. Specify the Source Interface by doing one of the following:

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

   2. 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.

4. Specify the Destination Interface by doing one of the following:

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

   2. 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.

5. Press Enter for Packet Type > select smtp-st.

6. Press Esc > 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.