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00 Nat

Network Address Translation (NAT) is a method for translating private IP addresses into public IP addresses, allowing communication with the internet. There are different types of NAT, including Static NAT, Dynamic NAT, and Port Address Translation (PAT), each with specific configurations and use cases. NAT helps conserve public IP addresses by enabling multiple private IPs to share a single public IP through techniques like port number differentiation.

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40 views2 pages

00 Nat

Network Address Translation (NAT) is a method for translating private IP addresses into public IP addresses, allowing communication with the internet. There are different types of NAT, including Static NAT, Dynamic NAT, and Port Address Translation (PAT), each with specific configurations and use cases. NAT helps conserve public IP addresses by enabling multiple private IPs to share a single public IP through techniques like port number differentiation.

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maroush2011
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We take content rights seriously. If you suspect this is your content, claim it here.
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Network Address Translation (NAT)

 NAT is the method of translation of private IP address into public IP.


 In order to communicate with internet, we need registered public IP.
 NAT can be configured on Routers, Firewalls.
 Private IP Addresses:
Class Private IP Range
A 10.0.0.0 To 10.255.255.255
B 172.16.0.0 To 172.31.255.255
C 192.168.0.0 To 192.168.255.255

 Types of NAT:
 Static NAT:
 One to one mapping done by manually.
 Every Private IP needs one registered Public IP address, (one to one).
 Syntax Of Static :
 ROUTER (config)# ip nat inside source static <privet-ip> <public-ip>
 ROUTER(config)#interface fa<Port-No>
 ROUTER(config-if)#ip nat inside
 ROUTER(config-if)#exit
 ROUTER(config)#interface serial<Port-No>
 ROUTER(config-if)#ip nat outside
 ROUTER(config-if)#exit
 ROUTER(config)#
 Dynamic NAT:
 To map Private IP address to a Public IP address from out of a pool of registered IP
addresses.
 Syntax Of Dynamic:
 Router(config)#access-list <List-No> permit <NW- ID> <W.C.M>
 Router(config)# ip nat pool < pool-name> <Starting public IP> <End Public IP> netmask
<Subnet-mask>
 ROUTER(config)# ip nat inside source list <List-No> pool < Pool-Name>
 ROUTER(config)#interface fa<Port-No>
 ROUTER(config-if)#ip nat inside
 ROUTER(config-if)#exit
 ROUTER(config)#interface serial<Port-No>
 ROUTER(config-if)#ip nat outside
 ROUTER(config-if)#exit
 ROUTER(config)#

 Port Address Translation [PAT/NAT]:


 It translates so many private IP address using just single Public IP address.
 uses unique source port numbers on the Inside Global IP address to distinguish between
translations.
 total number could theoretically be as high as 65,536 per IP address.
 PAT will attempt to preserve the original source port, if this source port is already allocated
PAT will attempt to find the first available port number
 NAT overload can use more than 65,000 ports, allowing it to scale well without needing
many registered IP addresses—in many cases, needing only one outside global IP address.
 Syntax Of PAT/NAT:
 Router(config)# access-list <List-No> permit <NW- ID> <W.C.M>
 Router(config)# ip nat inside source list <list-no> interface <port-no> overload

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