NAT configuration

INSIDE LOCAL              INSIDE GLOBAL                     OUTSIDE GLOBAL

First define your interfaces:

– Go to the internal interface en make it inside local:

en
conf t
interface FastEthernet 0/1
ip nat inside
control+z

– Go to the external interface and make it inside global:
en
conf t
interface FastEthernet 0/1
ip nat outside
control+z

– Save  the config
copy running-config startup-config
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PAT with and pool of internal addresses

Internal addresses NAT outside with an access list!

– Make and access-list with the internal addresses
en
conf t
ip access-list standard INSIDE_NAT_ADDRESSES
permiet

– Direct the the pool of internal addresses the outside address
ip nat inside source list INSIDE_NAT_ADDRESSES (interface or pool of addresseses) interface fastethernet 0/1 (or other external port) overload

One address NAT outside with an access list!

– View translations with the command
show ip nat translation

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Dynamic NAT  from an local pool to an pool of external (public) addresses

-Define your external (public) ip-addresses
en
conf t
ip nat pool OUTSIDE_PUBLIC netmask 255.255.255.248

-then create the PAT
ip nat inside source list pool OUTSIDE_PUBLIC overload

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Static NAT

All the ports direct to internal machine:
ip nat inside source static

Redirect only port 80 from external to one internal device:
ip nat inside source static tcp local_ip (inside local) 80 Extern_IP (outside global) 80 (static NAT for port 80)

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