MAC Address
MAC stands for media access control. A MAC address is the hardware address
of a device connected to a network. The MAC address is a unique identifier for a
device with an Ethernet interface. It is composed of two parts: 3 bytes of data
that corresponds to the manufacturer ID (unique for each manufacturer), plus 3
bytes that are often used as the product’s serial number.
NAT
A network address translator is defined by RFC 1631. It enables a LAN network
to use one set of IP addresses for internal traffic. A NAT box located where the
LAN meets the Internet provides the necessary IP address translation. This helps
provide a sort of firewall and allows for a wider address range to be used
internally without danger of conflict. Using the router’s NAT capability, you can
access the Internet from any computer on your home network without having to
purchase more IP addresses from your ISP.
Port
Network clients (LAN PC) uses port numbers to distinguish one network
application/protocol from another. Below is a list of common applications and
protocol/port numbers.