Datasheet

Lab – Configuring Port Address Translation (PAT)
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Gateway# show ip nat statistics
Step 3: Remove the pool of useable public IP addresses.
Gateway(config)# no ip nat pool public_access 209.165.200.225 209.165.200.230
netmask 255.255.255.248
Step 4: Remove the NAT translation from inside source list to outside pool.
Gateway(config)# no ip nat inside source list 1 pool public_access overload
Step 5: Associate the source list with the outside interface.
Gateway(config)# ip nat inside source list 1 interface serial 0/0/1 overload
Step 6: Test the PAT configuration.
a. From each PC, ping the 192.31.7.1 address on the ISP router.
b. Display NAT statistics on the Gateway router.
Gateway# show ip nat statistics
Total active translations: 3 (0 static, 3 dynamic; 3 extended)
Peak translations: 3, occurred 00:00:19 ago
Outside interfaces:
Serial0/0/1
Inside interfaces:
GigabitEthernet0/1
Hits: 24 Misses: 0
CEF Translated packets: 24, CEF Punted packets: 0
Expired translations: 0
Dynamic mappings:
-- Inside Source
[Id: 2] access-list 1 interface Serial0/0/1 refcount 3
Total doors: 0
Appl doors: 0
Normal doors: 0
Queued Packets: 0
c. Display NAT translations on Gateway.
Gateway# show ip nat translations
Pro Inside global Inside local Outside local Outside global
icmp 209.165.201.18:3 192.168.1.20:1 192.31.7.1:1 192.31.7.1:3
icmp 209.165.201.18:1 192.168.1.21:1 192.31.7.1:1 192.31.7.1:1
icmp 209.165.201.18:4 192.168.1.22:1 192.31.7.1:1 192.31.7.1:4
Reflection
What advantages does PAT provide?
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Answers will vary, but should include that PAT minimizes the number of public addresses needed to provide
Internet access, and that PAT, like NAT, serves to “hide” private addresses from outside networks.