Fortinet FortiGate-800 manual 324

Glossary

LAN, Local Area Network: A computer network that spans a relatively small area. Most LANs connect workstations and personal computers. Each computer on a LAN is able to access data and devices anywhere on the LAN. This means that many users can share data as well as physical resources such as printers.

MAC address, Media Access Control address: A hardware address that uniquely identifies each node of a network.

MIB, Management Information Base: A database of objects that can be monitored by an SNMP network manager.

Modem: A device that converts digital signals into analog signals and back again for transmission over telephone lines.

MTU, Maximum Transmission Unit: The largest physical packet size, measured in bytes, that a network can transmit. Any packets larger than the MTU are divided into smaller packets before being sent. Ideally, you want the MTU your network produces to be the same as the smallest MTU of all the networks between your machine and a message's final destination. If your messages are larger than one of the intervening MTUs, they get broken up (fragmented), which slows down transmission speeds.

Netmask: Also called subnet mask. A set of rules for omitting parts of a complete IP address to reach a target destination without using a broadcast message. It can indicate a subnetwork portion of a larger network in TCP/IP. Sometimes referred to as an Address Mask.

NTP, Network Time Protocol: Used to synchronize the time of a computer to an NTP server. NTP provides accuracies to within tens of milliseconds across the Internet relative to Coordinated Universal Time (UTC).

Packet: A piece of a message transmitted over a packet-switching network. One of the key features of a packet is that it contains the destination address in addition to the data. In IP networks, packets are often called datagrams.

Ping, Packet Internet Grouper: A utility used to determine whether a specific IP address is accessible. It works by sending a packet to the specified address and waiting for a reply.

POP3, Post Office Protocol: A protocol used to transfer e-mail from a mail server to a mail client across the Internet. Most e-mail clients use POP.

PPP, Point-to-Point Protocol: A TCP/IP protocol that provides host-to-network and router-to-router connections.

PPTP, Point-to-Point Tunneling Protocol: A Windows-based technology for creating VPNs. PPTP is supported by Windows 98, 2000, and XP. To create a PPTP VPN, your ISP's routers must support PPTP.

Port: In TCP/IP and UDP networks, a port is an endpoint to a logical connection. The port number identifies what type of port it is. For example, port 80 is used for HTTP traffic.

Protocol: An agreed-upon format for transmitting data between two devices. The protocol determines the type of error checking to be used, the data compression method (if any), how the sending device indicates that it has finished sending a message, and how the receiving device indicates that it has received a message.

RADIUS, Remote Authentication Dial-In User Service: An authentication and accounting system used by many Internet Service Providers (ISPs). When users dial into an ISP they enter a user name and password. This information is passed to a RADIUS server, which checks that the information is correct, and then authorizes access to the ISP system.

Router: A device that connects LANs into an internal network and routes traffic between them.

Routing: The process of determining a path to use to send data to its destination.

Routing table: A list of valid paths through which data can be transmitted.

Server: An application that answers requests from other devices (clients). Used as a generic term for any device that provides services to the rest of the network such as printing, high capacity storage, and network access.

SMTP, Simple Mail Transfer Protocol: In TCP/IP networks, this is an application for providing mail delivery services.

SNMP, Simple Network Management Protocol: A set of protocols for managing networks. SNMP works by sending messages to different parts of a network. SNMP-compliant devices, called agents, store data about themselves in Management Information Bases (MIBs) and return this data to the SNMP requesters.

324 Fortinet Inc.