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.
Application | Protocol | Port Number |
Telnet | TCP | 23 |
FTP | TCP | 21 |
SMTP | TCP | 25 |
POP3 | TCP | 110 |
H.323 | TCP | 1720 |
SNMP | UCP | 161 |
SNMP Trap | UDP | 162 |
HTTP | TCP | 80 |
PPTP | TCP | 1723 |
PC Anywhere | TCP | 5631 |
PC Anywhere | UDP | 5632 |
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