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Cisco ASA Series Firewall ASDM Configuration Guide
Chapter5 Configuring Twice NAT (ASA 8.3 and Later)
Configuring Twice NAT
Step8 (Optional) For NAT46, check the Use one-to-one address translation check box. For NAT46, specify
one-to-one to translate the first IPv4 address to the first IPv6 address, the second to the second, and so
on. Without this option, the IPv4-embedded method is used. For a one-to-one translation, you must use
this keyword.
Step9 (Optional) Configure NAT options in the Options area.
a. Enable rule —Enables this NAT rule. The rule is enabled by default.
b. (For a source-only rule) Translate DNS replies that match this rule—Rewrites the DNS A record in
DNS replies. Be sure DNS inspection is enabled (it is enabled by default). You cannot configure
DNS modification if you configure a destination address. See the “DNS and NAT” section on
page 3-31 for more information.
c. Disable Proxy ARP on egress interface—Disables proxy ARP for incoming packets to the mapped
IP addresses. See the “Mapped Addresses and Routing” section on page 3-22 for more information.
d. Direction—To make the rule unidirectional, choose Unidirectional. The default is Both. Making the
rule unidirectional prevents traffic from initiating connections to the real addresses.
e. Description—Adds a description about the rule up to 200 characters in length.