TMS zl Management and Configuration Guide ST.1.1.100430

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Overview
Network Address Translation (NAT)
Firewall Event Severity
Each event has an associated severity level. From greatest to least severity,
these levels are as follows:
■ Critical—Error may lead to failure
■ Major—Error may lead to failure or faulty functioning
■ Minor—Error may lead to faulty functioning
■ Warning—Error should be corrected
■ Information—Notification of significant events
Network Address Translation (NAT)
In routing mode, the TMS zl Module can apply NAT to network traffic. (Monitor
mode does not support NAT.) Although the module’s firewall provides the NAT
capability, NAT policies are entirely separate from the firewall access policies
for increased flexibility. However, you must configure firewall access policies
to permit the traffic to which NAT policies apply.
The module can perform the following types of NAT:
■ Source NAT
With source NAT, the TMS zl Module translates the source IP address of
a packet to a new IP address, which is valid in the network to which the
packet is destined. The module supports static and dynamic source NAT:
•Many-to-one
Many local devices share the same IP address in the destination
network. However, each local device has its own source port. That is,
the module translates each source IP address to the same new IP
address but to a different source port. Return traffic to the local
devices is all destined to the same IP address, but to different ports.
Thus the module can forward return traffic to the correct device.
•One-to-one
Each local device receives its own new IP address for the destination
network.