ICND Interconnecting Cisco Networking Devices Part 1

TCP differs from UDP primarily in two ways: it provides synchronized communication to ensure that both ends of the connection are in agreement about the state of the communication, and it provides sequence numbering of packets to ensure data is received in the correct order. These features enable reliable, ordered, and error-checked delivery of a stream of packets. UDP, on the other hand, does not offer these reliability features and is used for faster, connectionless communication.

One-way NAT is used when traffic that originates outside the network must be routed to internal hosts. This configuration helps manage situations where internal hosts use private IP addresses that are not directly accessible from the internet. By implementing one-way NAT, the network administrator can translate the destination IP address of incoming packets from the outside network to the appropriate internal private IP address, allowing external sources to communicate with internal hosts. This setup is crucial for services that need to be accessed from outside the network, such as web servers or mail servers hosted internally.