![\"\"](\"http:\/\/wiki.thomasandsofia.com\/wp-content\/uploads\/2017\/01\/nat1.png\")
<\/a><\/p>\nUnderstanding the need for NAT<\/h2>\n\n- The Internet is just a massive network of networks<\/li>\n
- So many devices connected, we ran out of IPv4 IP addresses<\/li>\n
- NAT (Network Address Translation) allows many devices to share an Internet IP Address<\/li>\n<\/ul>\n
How NAT Works<\/h3>\n\n- Several devices on Private Network that want to access the Internet, but you only have 1 public IP.\n
\n- .1.50 wants to access a web page.\u00a0 Source IP:Port = 192.168.1.50:6751\n
\n- NAT converts to Source IP:Port = 200.1.1.1:6751 and stores in the NAT Table<\/li>\n<\/ul>\n<\/li>\n
- .1.51 wants to access a web page.\u00a0 Source IP:Port = 192.168.1.51:1536\n
\n- NAT converts to Source IP:Port = 200.1.1.1:1536<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<\/li>\n
- 65,535 Ports available.\n
\n- *IF* two PCs request the same Source Port, the Router will assign an available Port two one of the requests and store the change in the NAT Table.\n
\n- .1.50:6751=200.1.1.1:6751, .1.51:6751=200.1.1.1:4567<\/li>\n
- This type of address translation is commonly called PAT, Port Address Translation, or “NAT Overload”<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<\/li>\n
- Static NAT (Network Overload) will assign a 1:1 translation if specific traffic needs to go to a specific IP\n
\n- 192.168.1.20 -> 200.1.1.2 (Static IP provided by ISP)<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n
Using the SDM<\/h3>\n
Basic NAT: Same as PAT, or NAT Overload<\/p>\n
Advanced NAT: Allows static mappings to allow traffic back into your network<\/p>\n
Starting with Basic NAT (Can add Advanced later)<\/p>\n
\n- Select Interface that connects to the Internet<\/li>\n
- Check all Interfaces you want to share with the Internet connection<\/li>\n
- Done!<\/li>\n<\/ul>\n
r1(config)#access-list 1 remark ACL Category 2\r\nr1(config)#access-list 1 permit 192.168.11.0 0.0.0.255\r\nr1(config)#interface fastethernet0\/0\r\nr1(config-if)#ip nat inside\r\nr1(config-if)#exit\r\nr1(config)#interface fastethernet0\/1\r\nr1(config-if)#ip nat inside\r\nr1(config-if)#exit\r\nr1(config)#ip nat inside source list 1 interface 0\/1 overload\r\n<\/pre>\n <\/p>\n
Show Commands<\/h3>\nshow ip nat translations<\/pre>\n <\/p>\n","protected":false},"excerpt":{"rendered":"
Understanding the need for NAT The Forms of NAT Configuring NAT using the SDM Understanding the need for NAT The Internet is just a massive network of networks So many devices connected, we ran out of IPv4 IP addresses NAT (Network Address Translation) allows many devices to share an Internet IP Address How NAT Works ..<\/p>\n
How NAT Works<\/h3>\n\n- Several devices on Private Network that want to access the Internet, but you only have 1 public IP.\n
\n- .1.50 wants to access a web page.\u00a0 Source IP:Port = 192.168.1.50:6751\n
\n- NAT converts to Source IP:Port = 200.1.1.1:6751 and stores in the NAT Table<\/li>\n<\/ul>\n<\/li>\n
- .1.51 wants to access a web page.\u00a0 Source IP:Port = 192.168.1.51:1536\n
\n- NAT converts to Source IP:Port = 200.1.1.1:1536<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<\/li>\n
- 65,535 Ports available.\n
\n- *IF* two PCs request the same Source Port, the Router will assign an available Port two one of the requests and store the change in the NAT Table.\n
\n- .1.50:6751=200.1.1.1:6751, .1.51:6751=200.1.1.1:4567<\/li>\n
- This type of address translation is commonly called PAT, Port Address Translation, or “NAT Overload”<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<\/li>\n
- Static NAT (Network Overload) will assign a 1:1 translation if specific traffic needs to go to a specific IP\n
\n- 192.168.1.20 -> 200.1.1.2 (Static IP provided by ISP)<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n
Using the SDM<\/h3>\n
Basic NAT: Same as PAT, or NAT Overload<\/p>\n
Advanced NAT: Allows static mappings to allow traffic back into your network<\/p>\n
Starting with Basic NAT (Can add Advanced later)<\/p>\n
\n- Select Interface that connects to the Internet<\/li>\n
- Check all Interfaces you want to share with the Internet connection<\/li>\n
- Done!<\/li>\n<\/ul>\n
r1(config)#access-list 1 remark ACL Category 2\r\nr1(config)#access-list 1 permit 192.168.11.0 0.0.0.255\r\nr1(config)#interface fastethernet0\/0\r\nr1(config-if)#ip nat inside\r\nr1(config-if)#exit\r\nr1(config)#interface fastethernet0\/1\r\nr1(config-if)#ip nat inside\r\nr1(config-if)#exit\r\nr1(config)#ip nat inside source list 1 interface 0\/1 overload\r\n<\/pre>\n <\/p>\n
Show Commands<\/h3>\nshow ip nat translations<\/pre>\n <\/p>\n","protected":false},"excerpt":{"rendered":"
Understanding the need for NAT The Forms of NAT Configuring NAT using the SDM Understanding the need for NAT The Internet is just a massive network of networks So many devices connected, we ran out of IPv4 IP addresses NAT (Network Address Translation) allows many devices to share an Internet IP Address How NAT Works ..<\/p>\n
- \n
- .1.50 wants to access a web page.\u00a0 Source IP:Port = 192.168.1.50:6751\n
- \n
- NAT converts to Source IP:Port = 200.1.1.1:6751 and stores in the NAT Table<\/li>\n<\/ul>\n<\/li>\n
- .1.51 wants to access a web page.\u00a0 Source IP:Port = 192.168.1.51:1536\n
- \n
- NAT converts to Source IP:Port = 200.1.1.1:1536<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<\/li>\n
- 65,535 Ports available.\n
- \n
- *IF* two PCs request the same Source Port, the Router will assign an available Port two one of the requests and store the change in the NAT Table.\n
- \n
- .1.50:6751=200.1.1.1:6751, .1.51:6751=200.1.1.1:4567<\/li>\n
- This type of address translation is commonly called PAT, Port Address Translation, or “NAT Overload”<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<\/li>\n
- Static NAT (Network Overload) will assign a 1:1 translation if specific traffic needs to go to a specific IP\n
- \n
- 192.168.1.20 -> 200.1.1.2 (Static IP provided by ISP)<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n
Using the SDM<\/h3>\n
Basic NAT: Same as PAT, or NAT Overload<\/p>\n
Advanced NAT: Allows static mappings to allow traffic back into your network<\/p>\n
Starting with Basic NAT (Can add Advanced later)<\/p>\n
- \n
- Select Interface that connects to the Internet<\/li>\n
- Check all Interfaces you want to share with the Internet connection<\/li>\n
- Done!<\/li>\n<\/ul>\n
r1(config)#access-list 1 remark ACL Category 2\r\nr1(config)#access-list 1 permit 192.168.11.0 0.0.0.255\r\nr1(config)#interface fastethernet0\/0\r\nr1(config-if)#ip nat inside\r\nr1(config-if)#exit\r\nr1(config)#interface fastethernet0\/1\r\nr1(config-if)#ip nat inside\r\nr1(config-if)#exit\r\nr1(config)#ip nat inside source list 1 interface 0\/1 overload\r\n<\/pre>\n
<\/p>\n
Show Commands<\/h3>\n
show ip nat translations<\/pre>\n
<\/p>\n","protected":false},"excerpt":{"rendered":"
Understanding the need for NAT The Forms of NAT Configuring NAT using the SDM Understanding the need for NAT The Internet is just a massive network of networks So many devices connected, we ran out of IPv4 IP addresses NAT (Network Address Translation) allows many devices to share an Internet IP Address How NAT Works ..<\/p>\n
- 192.168.1.20 -> 200.1.1.2 (Static IP provided by ISP)<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n
- *IF* two PCs request the same Source Port, the Router will assign an available Port two one of the requests and store the change in the NAT Table.\n