Static address translation establishes a one-to-one
mapping between a local and global address or local and global address/port
pair. When you specify a static address translation or address/port
pair translation, you issue commands to indicate how the translation
is applied, along with more specific variables that further define
the type of translation.
Caution:
You must mark interfaces that participate in NAT
translation as on the inside or the outside network. See Specifying Inside and Outside Interfaces for details.
Creating Static Inside Source Translations
You use the ip nat inside source static command to create static translations from a local IP address to
a global IP address, and to untranslate the destination
address when a packet returns from the outside network to the inside
network. When you configure traditional NAT (both basic NAT and NAPT),
you only need to use this command alone. However, when you configure
twice NAT, you must also use ip
nat outside source static .
The ip nat inside source static command creates a simple (IP address only) or extended (IP address,
port, and protocol) entry in the translation table that maps the two
addresses.
ip
nat inside source static
Use to create static translations for a source address
(or address/port pair) when routing a packet from the inside network
to the outside network, and to untranslate the
destination address (or address/port pair) when a packet returns from
the outside network to the inside network.
A static translation created with the ip
nat inside source static command enables any outside
host to contact the inside host by using the inside global address
of the inside host. A static translation can be used by traffic that
is initiated in either direction
Example 1—Simple address translation
host (config) # ip nat inside source static
10.1.2.3 171.69.68.10
Less commonly used, outside source translation
enables you to set up translation between two non-unique or not publicly
routable networks (for example, two separate networks that use overlapping
IP address blocks).
ip
nat outside source static
Use to translate the source address when routing a packet
from the outside network to the inside network, and to untranslate the destination address when a packet travels from the inside network
to the outside network.
Creates a simple (IP address only) or extended (IP address,
protocol, and port) entry in the translation table that maps the two
addresses.
A static translation created with the ip
nat outside source static command enables any inside
host to contact the outside host by using the outside local address
of the outside host. A static translation can be used by traffic that
is initiated in either direction.
Example 1—Simple address translation
host (config) # ip nat outside source static 171.69.68.10
10.1.2.3
