What is a disadvantage of NAT?
- There is no end-to-end addressing.
- The router does not need to alter the checksum of the IPv4 packets.
- The costs of readdressing hosts can be significant for a publicly addressed network.
- The internal hosts have to use a single public IPv4 address for external communication.
Many Internet protocols and applications depend on end-to-end addressing from the source to the destination. Because parts of the header of the IP packets are modified, the router needs to alter the checksum of the IPv4 packets. Using a single public IP address allows for the conservation of legally registered IP addressing schemes. If an addressing scheme needs to be modified, it is cheaper to use private IP addresses.