
14-29
Cisco Security Appliance Command Line Configuration Guide
OL-6721-01
Chapter 14 Applying NAT
Bypassing NAT
Bypassing NAT
This section describes how to bypass NAT. You might want to bypass NAT when you enable NAT control.
You can bypass NAT using identity NAT, static identity NAT, or NAT exemption. See the “Bypassing
NAT when NAT Control is Enabled” section on page 14-9 for more information about these methods.
This section includes the following topics:
• Configuring Identity NAT, page 14-29
• Configuring Static Identity NAT, page 14-30
• Configuring NAT Exemption, page 14-31
Configuring Identity NAT
Identity NAT translates the real IP address to the same IP address. Only “translated” hosts can create
NAT translations, and responding traffic is allowed back.
Figure 14-23 shows a typical identity NAT scenario.
Figure 14-23 Identity NAT
Note If you change the NAT configuration, and you do not want to wait for existing translations to time out
before the new NAT information is used, you can clear the translation table using the clear xlate
command. However, clearing the translation table disconnects all current connections that use
translations.
To configure identity NAT, enter the following command:
hostname(config)# nat (
real_interface
) 0
real_ip
[
mask
[dns] [outside | [norandomseq]
[[tcp]
tcp_max_conns
[
emb_limit
]] [udp
udp_max_conns
]]]
See the “Configuring Dynamic NAT or PAT” section on page 14-22 for information about the options.
For example, to use identity NAT for the inside 10.1.1.0/24 network, enter the following command:
hostname(config)# nat (inside) 0 10.1.1.0 255.255.255.0
209.165.201.1 209.165.201.1
Inside Outside
209.165.201.2 209.165.201.2
130033
Security
Appliance
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