Network and device configuration
If the device is set to explicit proxy mode, you must explicitly configure your internal mail server
to relay email traffic to the device. The device scans the email traffic before forwarding it, on
behalf of the sender, to the external mail server. The external mail server then forwards the
email message to the recipient.
In a similar way, the network must be configured so that incoming email messages from the
Internet are delivered to the device, not the internal mail server.
Figure 5: Relaying email traffic
The device scans the traffic before forwarding it, on behalf of the sender, to the internal mail
server for delivery, as shown in
Figure 5: Relaying email traffic
.
For example, an external mail server can communicate directly with the device, although traffic
might pass through several network servers before reaching the device. The perceived path is
from the external mail server to the device.
Protocols
To scan a supported protocol, you must configure your other network servers or client computers
to route that protocol through the device, so that no traffic bypasses the device.
Firewall rules
Explicit proxy mode invalidates any firewall rules set up for client access to the Internet. The
firewall sees only the IP address information for the device, not the IP addresses of the clients,
so the firewall cannot apply its Internet access rules to the clients.
Where to place the device
Configure the network devices so that traffic needing to be scanned is sent to the device. This
is more important than the location of the device.
Pre-installation
Considerations about Network Modes
McAfee Email and Web Security Appliance 5.5 Installation Guide
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Summary of Contents for Email and Web Security Appliance 5.5
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