Post-gateway deployment
Note:
This model may be implemented with one or more SMTP gateway MTAs
and one or more Scanner hosts.
Figure 1-3
shows Symantec Mail Security deployed after MTAs at the firewall.
Figure 1-3
Post-Gateway deployment
MTAs at the gateway layer accept unfiltered mail from the Internet then relay it
to Symantec Mail Security. The system filters mail from the gateway layer and
relays mail to other MTAs downstream.
Advantages
Your network configuration may require that you place your Scanner hosts with
your SMTP gateway MTA in a "demilitarized zone" between two firewalls.
■
If you have a customized MTA or specific business needs, then running this
configuration may outweigh the extra overhead and loss of functionality.
Considerations
Post-gateway deployment limits the functionality of Scanners and may decrease
system throughput.
■
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
17
Planning your deployment
Deployment models