Cisco ASA 5505 User Manual

Page 618

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31-12

Cisco ASA 5500 Series Configuration Guide using the CLI

Chapter 31 Configuring Twice NAT

Configuring Twice NAT

Step 6

nat

[(real_ifc,mapped_ifc)]

[line | {after-auto [line]}]

source dynamic

{real-obj | any}

{mapped_obj [interface] | [pat-pool

mapped_obj [round-robin] [extended]

[flat [include-reserve]] [interface] |

interface

} [destination static {mapped_obj

| interface} real_obj]

[service mapped_dest_svc_obj

real_dest_svc_obj] [dns] [inactive]

[description desc]

Example:

hostname(config)# nat (inside,outside)

source dynamic MyInsNet interface

destination static Server1 Server1

description Interface PAT for inside

addresses when going to server 1

Configures dynamic PAT (hide). See the following guidelines:

Interfaces—(Required for transparent mode) Specify the real
and mapped interfaces. Be sure to include the parentheses in
your command. In routed mode, if you do not specify the real
and mapped interfaces, all interfaces are used; you can also
specify the keyword any for one or both of the interfaces.

Section and Line—(Optional) By default, the NAT rule is
added to the end of section 1 of the NAT table (see the

“NAT

Rule Order” section on page 29-20

). If you want to add the

rule into section 3 instead (after the network object NAT
rules), then use the after-auto keyword. You can insert a rule
anywhere in the applicable section using the line argument.

Source addresses:

Real—Specify a network object, group, or the any
keyword (see

Step 1

). Use the any keyword if you want

to translate all traffic from the real interface to the
mapped interface.

Mapped—Configure one of the following:

- Network object—Specify a network object that contains
a host address (see

Step 2

).

- pat-pool—Specify the pat-pool keyword and a network
object or group that contains multiple addresses (see

Step 2

).

- interface—(Routed mode only) Specify the interface
keyword alone to only use interface PAT. When specified
with a PAT pool or network object, the interface
keyword enables interface PAT fallback. After the PAT IP
addresses are used up, then the IP address of the mapped
interface is used. For this option, you must configure a
specific interface for the mapped_ifc.

(continued)

Command

Purpose

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