Question

Compare and contrast the translation table at NAT router, i.e., (a) Single external IP (b) Multiple external IPs (c) IP along with port number.

Answer 1

NETWORK ADDRESS TRANSLATION :
to access the internet, one public ip address is needed but we use a private ip address in our private network. the theme of NAT is to allow multiple devices to access the internet through a single public address. to acheve this the translation of private ip address to a public ip address is reqyired

NAT working:

the border router is configured for nat the router which has one interface in local network and one interface in the globla network. when a packet traverse outside the local network then NAT converts that local(private ) ip address to global(public) ip address. when a packet enters the local network the global (public) ip address is converted to a local (private) ip address

SINGLE EXTERNAL IP: this is the actual ip address of the destination host in the local network after translation as outside local address one to one combination

MULTIPLE EXTERNAL IP: this is the outside host as seen form the outside network. it is the ip address of the outside destination host before translation as outside global address one to many combination

Ip along with the port number:

this is also known as nat overload in this by checking the port number it will transfer the data to the destination it is easy among all

Advantages of NAT:

nat conserves legally registed ip address

it provides privacy as the device ip address semding and receivng the traffic will be hidden

eliminates address renumbering when a network evolves

comment if you have any doubts