Network Address Translation(NAT)
NAT is a process where a network device allocates a public address to the computers in the private network. NAT helps to: eliminate re-assigning each host new IP address when changing a new ISP, eliminate the need to re-address all hosts that require external access which saves time and money, conserves addresses through application port-level multiplexing, and protects network security.
There are 2 types of NAT translation :
Static NAT
This is designed to allow one-to-one mapping of local(private) and global(public) address. Allowing the internal host which have private IP address to still be reachable over the internet.
Dynamic NAT
This is designed to map a private IP address to a public IP address, meaning many-to-many mapping. The NAT router in the network would keep a table of the registered IP addresses, and when a private IP address request access into the network, the NAT router would choose a IP address from the table that is not use by another host and give it to the one who is requesting access.
Port Address Translation(PAT)
PAT, is an extension of NAT, uses unique source port numbers on the inside global IP address to differentiate between translations, which is a many-to-one mapping. Most of our home network uses PAT.
This is designed to map a private IP address to a public IP address, meaning many-to-many mapping. The NAT router in the network would keep a table of the registered IP addresses, and when a private IP address request access into the network, the NAT router would choose a IP address from the table that is not use by another host and give it to the one who is requesting access.
Port Address Translation(PAT)
PAT, is an extension of NAT, uses unique source port numbers on the inside global IP address to differentiate between translations, which is a many-to-one mapping. Most of our home network uses PAT.
REFERENCE : http://www.webopedia.com/TERM/N/NAT.html
http://www.cisco.com/en/US/tech/tk648/tk361/technologies_tech_note09186a0080094
831.shtml
http://www.cisco.com/en/US/tech/tk648/tk361/technologies_tech_note09186a0080094
831.shtml
ENNK lecture notes
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From this post, I learnt that there are two types of network address translation (NAT). The static NAT and the dynamic NAT. It is the process where a network device allocates a public address to computers in private networks. This saves time and money, as it conserves addresses through application port-level multiplexing, and protects network security. The static NAT allows one-to-one mapping of local and global addresses, allowing the internal host which have private IP address to still be reachable over the internet. The dynamic NAT allows many-to-many mapping. The NAT router would keep a table of registered addresses and when a private IP address request access, the router would choose a IP address from the table that is not used by another host.
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