NAT – Part 4 (PAT Configuration with Packet Tracer) - www.ipcisco.com : www.ipcisco.com
Content Protection by DMCA.com

PAT Configuration

with Packet Tracer




************************************************************
WouLd YoU LiKe To Learn How to Use PAcket TraceR and PracTice CCNA LAbs
on PaCKet TrAcEr??? Here is My Courses on UDemY!!
CISCO PACKET TRACER HOW TO GUIDE
CISCO PACKET TRACER CCNA LABS ADVENTURE 1
CISCO PACKET TRACER CCNA LABS ADVENTURE 2
************************************************************


In some cases there can be hundreds of inside local addresses and at the same time your global ip addresses can be limited.At this time you can use PAT instead of static and dynamic NAT translation.

Here, with PAT(Port Address Translation), we translate each PC to a unique port number of a single public address.

You can DOWNLOAD Packet Tracer example with .pkt format HERE.

Firstly we identify the interfaces as inside and outside as before static and dynamic NAT configurations. Here, we will use the same topology like Dynamic NAT configuration article. Because, for PAT configuration, we need a small change on the configuration.

port address translation (PAT) topology

PAT (Port Address Translation) Configuration Topology

Here, we will start with the IP address configurations firstly.

Our PCs on Packet Tracer will be configured with below IP addresses.

PC0 : 10.0.0.2 255.255.255.0 GW:10.0.0.1
PC1 : 10.0.0.3 255.255.255.0 GW:10.0.0.1
PC2 : 10.0.0.4 255.255.255.0 GW:10.0.0.1

Router1(config)# interface FastEthernet0/0
Router1(config-if)# ip address 10.0.0.1 255.255.255.0
Router1(config-if)# no shutdown
Router1(config-if)# exit
Router1(config)# interface FastEthernet0/1
Router1(config-if)# ip address 212.100.100.2 255.255.255.0
Router1(config-if)# no shutdown
Router1(config-if)# exit

Router2(config)# interface FastEthernet0/0
Router2(config-if)# ip address 212.100.100.1 255.255.255.0
Router2(config-if)# no shutdown
Router2(config-if)# exit
Router2(config)# ip default-gateway 212.100.100.2
Router2(config)# no ip routing

Now, let’s do the classical NAT configuration and plus PAT configuration (overload).

Router1 (config)# int e0/0 
Router1 (config-if)# ip nat inside
Router1 (config-if)# exit
Router1 (config)# int s0/0 
Router1 (config-if)# ip nat outside
Router1 (config-if)# exit

After that we will use the below commands for PAT configuration:

Router1 (config)# access-list 10 permit 10.0.0.0 0.0.0.255
Router1 (config)# ip nat pool IPCISCO 50.50.50.80 50.50.50.80 netmask 255.255.255.0
Router1 (config)# ip nat inside source list 10 pool IPCISCO overload

Here, any match interface with access-list 10, will be translated with overload to the serial interface IP address. The secret key word of PAT configuration is “overload“.

Let’s check the nat table on Router1.

Router1# show ip nat translations 
Pro  Inside global     Inside local       Outside local      Outside global
icmp 50.50.50.80:1     10.0.0.4:1         212.100.100.1:1    212.100.100.1:1
icmp 50.50.50.80:2     10.0.0.4:2         212.100.100.1:2    212.100.100.1:2
icmp 50.50.50.80:3     10.0.0.4:3         212.100.100.1:3    212.100.100.1:3
icmp 50.50.50.80:4     10.0.0.4:4         212.100.100.1:4    212.100.100.1:4

PC0>ping 212.100.100.1
Pinging 212.100.100.1 with 32 bytes of data:

Reply from 212.100.100.1: bytes=32 time=1ms TTL=254
Reply from 212.100.100.1: bytes=32 time=0ms TTL=254
Reply from 212.100.100.1: bytes=32 time=0ms TTL=254
Reply from 212.100.100.1: bytes=32 time=1ms TTL=254

Ping statistics for 212.100.100.1:
    Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
    Minimum = 0ms, Maximum = 1ms, Average = 0ms

Router1#debug ip nat
IP NAT debugging is on
Router1#
NAT: s=10.0.0.2->50.50.50.80, d=212.100.100.1 [9]

NAT*: s=212.100.100.1, d=50.50.50.80->10.0.0.2 [32]

NAT: s=10.0.0.2->50.50.50.80, d=212.100.100.1 [10]

NAT*: s=212.100.100.1, d=50.50.50.80->10.0.0.2 [33]

NAT: s=10.0.0.2->50.50.50.80, d=212.100.100.1 [11]

NAT*: s=212.100.100.1, d=50.50.50.80->10.0.0.2 [34]

Router1#
NAT: s=10.0.0.2->50.50.50.80, d=212.100.100.1 [12]

NAT*: s=212.100.100.1, d=50.50.50.80->10.0.0.2 [35]

PC1>ping 212.100.100.1

Pinging 212.100.100.1 with 32 bytes of data:

Reply from 212.100.100.1: bytes=32 time=1ms TTL=254
Reply from 212.100.100.1: bytes=32 time=0ms TTL=254
Reply from 212.100.100.1: bytes=32 time=0ms TTL=254
Reply from 212.100.100.1: bytes=32 time=0ms TTL=254

Ping statistics for 212.100.100.1:
    Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
    Minimum = 0ms, Maximum = 1ms, Average = 0ms

Router1#
NAT: s=10.0.0.3->50.50.50.80, d=212.100.100.1 [7]

NAT*: s=212.100.100.1, d=50.50.50.80->10.0.0.3 [42]

NAT: s=10.0.0.3->50.50.50.80, d=212.100.100.1 [8]

NAT*: s=212.100.100.1, d=50.50.50.80->10.0.0.3 [43]

...

PC2>ping 212.100.100.1

Pinging 212.100.100.1 with 32 bytes of data:

Reply from 212.100.100.1: bytes=32 time=1ms TTL=254
Reply from 212.100.100.1: bytes=32 time=11ms TTL=254
Reply from 212.100.100.1: bytes=32 time=0ms TTL=254
Reply from 212.100.100.1: bytes=32 time=0ms TTL=254

Ping statistics for 212.100.100.1:
    Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
    Minimum = 0ms, Maximum = 11ms, Average = 3ms

Router1#
NAT: s=10.0.0.4->50.50.50.80, d=212.100.100.1 [23]

NAT*: s=212.100.100.1, d=50.50.50.80->10.0.0.4 [46]

NAT: s=10.0.0.4->50.50.50.80, d=212.100.100.1 [24]

NAT*: s=212.100.100.1, d=50.50.50.80->10.0.0.4 [47]
...

As a summary, PAT is used when you do not have enough public addresses for your inside network’s hosts. With PAT, you can use one public address and then you can multiple this address with port numbers.

You can DOWNLOAD Packet Tracer example with .pkt format HERE.

You can download “Packet Tracer” in Tools section.



************************************************************
WouLd YoU LiKe To Learn How to Use PAcket TraceR and PracTice CCNA LAbs
on PaCKet TrAcEr??? Here is My Courses on UDemY!!
CISCO PACKET TRACER HOW TO GUIDE
CISCO PACKET TRACER CCNA LABS ADVENTURE 1
CISCO PACKET TRACER CCNA LABS ADVENTURE 2
************************************************************



NAT – Part 1
NAT – Part 2 (Static NAT Configuration)
NAT – Part 3 (Dynamic NAT Configuration)
NAT – Part 4 (Port Address Translation)
NAT – Part 5 (NAT Troubleshooting)

You can reach the other NAT articles below:
Network Address Translation (NAT) – Part 1
Network Address Translation (NAT) – Part 2 (Static NAT Configuration)
Network Address Translation (NAT) – Part 3 (Dynamic NAT Configuration)
Network Address Translation (NAT) – Part 4 (Port Address Translation)

You can check the other Packet Tracer Examples below:

Common Cisco Router Configuration Example on Packet Tracer
Router DHCP Configuration Example on Packet Tracer
VTP Configuration Example on Packet Tracer
VLAN Configuration Example on Packet Tracer
STP Configuration Example on Packet Tracer
RSTP Configuration with Packet Tracer
STP Portfast Configuration with Packet Tracer
Inter VLAN Routing Configuration on Packet Tracer
Switch Virtual Interface (SVI) Configuration with Packet Tracer
BGP Configuration Example on Packet Tracer
Port Security Configuration Example on Packet Tracer
RIP Configuration Example on Packet Tracer
CDP Configuration Example on Packet Tracer
OSPF Area Types Example on Packet Tracer (Standard and Backbone Areas)
OSPF External Routes Example on Packet Tracer
OSPF Area Types Example on Packet Tracer (Stub, NSSA, Totally Stubby, Totally NSSA Areas)

Youn can join OUR Facebook Group with the below links!!!




About the Author
Gokhan Kosem is a telecommunation and network engineer. His ambition to IP networks and end-to-end system installation made him to prepare this web-site. By sharing his experiences about various networking protocols beside different system installation experiences and Cisco, Juniper, Alcatel-Lucent devices configurations, he is aimed to be helpful for his collegues in all over the world. He is currently lives in Istanbul, Turkey.

One comment for “NAT – Part 4 (PAT Configuration with Packet Tracer)”

1
Thiyagu

Thanks a lot Gokhan..finally i learned all NATs…have a nice day..

December 21st, 2012 at 22:18

Leave a Reply


Copy Protected by Chetan's WP-Copyprotect.