Symantec 10765539 Planning Guide - Page 23

Planning your deployment 23 Deployment models Post-gateway deployment Note: This model may be implemented with one or more SMTP gateway MTAs and one or more Scanner hosts. As shown below, MTAs at the gateway layer accept unfiltered mail from the Internet then relay it to Symantec Mail Security for SMTP. The system filters mail from the gateway layer and relays mail to other MTAs downstream. Figure 2-3 Post-Gateway deployment Advantages ■ If you have a customized MTA or specific business needs, then running this configuration may outweigh the extra overhead and loss of functionality. Considerations ■ This configuration limits Scanner functionality as IP-based defenses are nullified. ■ Unless the SMTP Gateway is performing filtering, all email is processed by the gateway (read, stored, and forwarded) then sent to the system, which must then read, filter, and take some action based on the verdict. Such redundancy may add overhead, thereby decreasing throughput.