Chapter 11: Scaling IP Addresses with Network Address Translation

Commands:

11.3.1 Static NAT

Router(config)# ip nat inside source static ip-add-local ip-add-global { private-ip public-ip}

LAN interface
Router(config-if)# ip nat inside

WAN interface
Router(config-if)# ip nat outside

 

11.3.2 Dynamic NAT

Router(config)# ip nat pool pool-name start-ip-add end-ip-add netmask mask
Router(config)# access-list number permit network-address wildcard-mask
Router(config)# ip nat inside source list number pool pool-name

LAN interface
Router(config-if)# ip nat inside

WAN interface
Router(config-if)# ip nat outside

 

11.3.3 NAT Overloading

Router(config)# ip nat pool pool-name start-ip-add end-ip-add netmask mask
Router(config)# access-list number permit network-address wildcard-mask
Router(config)# ip nat inside source list number pool pool-name
overload

LAN interface
Router(config-if)# ip nat inside

WAN interface
Router(config-if)# ip nat outside

 

11.3.4 TCP Load Distribution (Round-Robin or Rotary)

Router(config)#ip nat pool pool-name start-ip-add end-ip-add prefix-length bits type rotary
Router(config)# access-list acl-number permit ip-add-virtual-host {ip-add-virtual-host is the address another host will use to access this server}
Router(config)# ip nat inside destination list acl-number pool
pool-name

LAN interface
Router(config-if)# ip nat inside

WAN interface
Router(config-if)# ip nat outside

 

11.3.5 Overlapping Addresses Configuration

Inside pool
ip nat pool
name start-ip end-ip {netmask netmask | prefix-length prefix-length}

Outside pool
ip nat pool
name start-ip end-ip {netmask netmask | prefix-length prefix-length}

mapping for the acl and inside global pool
ip nat inside source list
access-list-number pool name [overload]

mapping for the acl and outside global pool
ip nat inside source list
access-list-number pool name [overload]

LAN interface
Router(config-if)# ip nat inside

WAN interface
Router(config-if)# ip nat outside

 

11.3.6 Verifying NAT

Router# show ip nat translations
Router#
show ip nat statistics

 

11.3.7 Troubleshooting NAT

Router#debug ip nat

 

11.3.8 Clearing NAT Translation

router#clear ip nat trans *

Miscellaneous commands
Router(config)# ip nat translation timeout seconds
Router(config)# ip nat translation [tcp, udp, dns]-timeout
seconds

 

11.4.3 Configuring PAT

7xx:Cisco1>Set IP PAT ON
7xx> SEt IP PAT POrt FTP 10.0.0.108

 

11.4.4 Monitoring PAT

7xx:Cisco1>show ip pat