NAT

Network Address Translation

Types of NAT

Static

Base Setup:

enable
conf t
interface {interface} {interface_#}
ip nat inside
exit
interface {interface} {{interface_#}
ip nat outside
exit
ip nat inside source static {source_ip} {static_ip}

Example:

enable
conf t
interface fastEthernet 0/0
ip nat inside
exit
interface serial 0/0/0
ip nat outside
exit
ip nat inside source static 10.0.0.2 50.0.0.1

PAT

Base Setup:

enable
conf t
interface {interface} {interface_#}
ip nat inside
exit
interface {interface} {{interface_#}
ip nat outside
exit
ip nat pool {pool_name} {start_ip} {stop_ip} netmask {subnet_mask}
access-list 1 permit {internal_network_address} {wildcard_subnet}
ip nat inside source list 1 pool {pool_name} overload

Example:

enable
conf t
interface fastEthernet 0/0
ip nat inside
exit
interface serial 0/0/0
ip nat outside
exit
ip nat pool test 30.0.0.120 30.0.0.120 netmask 255.0.0.0
access-list 1 permit 192.168.0.0 0.0.0.255
ip nat inside source list 1 pool test overload

Notes:

To show active nat stats

enable
show ip nat statistics