IP NAT and PAT Examples

Network Address Translation:
Cisco – IP NAT and PAT Examples:

Example 1:

  • Allow all outgoing traffic
  • PAT local network as
  • Allow incoming SMTP traffic (TCP Port 25) to that will be NAT’d as
  • Default Gateway

Interface Ethernet0
IP address
Description Outside-NIC
IP nat outside
IP virtual-reassembly

Interface FastEthernet0
IP address
Description Inside-NIC
IP NAT inside
IP virtual-reassembly

IP route

IP nat pool nat-1 netmask
IP nat inside source list 109 pool nat-1 overload
IP nat inside source static tcp 25 25 extendable no-alias

access-list 109 permit IP any

Example 2:
Example of Sub-Interface:

interface Serial0
no ip address
ip nat outside
ip virtual-reassembly
encapsulation frame-relay IETF
no fair-queue
service-module t1 timeslots 1-24
frame-relay lmi-type ansi

interface Serial0.1 point-to-point
ip address
ip access-group 109 in
ip nat outside
ip virtual-reassembly
frame-relay interface-dlci 500 IETF
crypto map myvpn

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