Triple DES. Also referred to as 3DES, a mode of the DES encryption algorithm that encrypts data three times. Three 64-bit keys are used, instead of one, for an overall key length of 192 bits (the first encryption is encrypted with second key, and the resulting cipher text is again encrypted with a third key).

Advanced Encryption Standard. A symmetric 128-bit block data encryption technique. AES works at multiple network layers simultaneously.

Address Resolution Protocol. The discovery protocol used by host computer systems to establish the correct mapping of Internet layer addresses, also known as IP addresses, to Media Access Control (MAC) layer addresses.

Dynamic Domain Name System. A method of keeping a domain name linked to a changing IP address as not all computers use static IP addresses.
The Dynamic DNS service allows you to alias a dynamic IP address to a static hostname, allowing your computer to be more easily accessed from various locations on the Internet. To use the service, you must first apply an account from DDNS service provider such as www.dyndns.org.
With DDNS supported by the Load Balancer, you apply a DNS name (e.g., www.abcd.com) for your server (e.g., Web server) from a DDNS server. The outside users can always access the web server using the www.abcd.com regardless of the WAN IP of the Load Balancer.
By contacting the DNS service each time the IP address provided by the ISP changes and subsequently updating the DNS database to reflect the change in IP address. In this way, even though a domain name's IP address will change often, other users do not have to know the changed IP address in order to connect with the other computer.

Data Encryption Standard. A popular symmetric-key encryption method developed in 1975 and standardized by ANSI in 1981 as ANSI X.3.92. DES uses a 56-bit key.

Dynamic Host Configuration Protocol. A protocol that is beginning to be used quite pervasively on end-system computers to automatically obtain an IP host address, subnet mask, and local gateway information. A DHCP server dynamically supplies this information in response to end-system broadcast requests.

Demilitarized Zone. A company that wants to host its own Internet services without sacrificing unauthorized access to its private network uses it. This special function allows multiple PCs on your LAN to be exposed to the Internet without any restrictions. This is useful for some network games, net meeting, or special applications. In order to enable these functions, you have to map one LAN IP address to one WAN IP address. However, because of the security risk, you should activate these functions only if they are necessary.

File Transfer Protocol. A bulk, TCP-based, transaction-oriented file transfer protocol used in TCP/IP networks, especially the Internet.

Software (programs or data) that has been written onto read-only memory (ROM). Firmware is a combination of software and hardware. ROMs, PROMs and EPROMs that have data or programs recorded on them are firmware.

In networking, a combination of hardware and software that links two different types of networks. Gateways between e-mail systems, for example, allow users on different e-mail systems to exchange messages.

Hyper Text Transfer Protocol. A TCP-based application-layer protocol used for communicating between web servers and web clients, also known as web browsers.

Internet Control Message Protocol. A network-layer protocol that provides feedback on errors and other information specifically pertinent to IP packet handling.

The Institute of Electrical and Electronics Engineers. A professional organization that develops communications and network standards-traditionally, link-layer LAN signaling standards.

Internet Protocol. The network-layer protocol in the TCP/IP stack used in the Internet. IP is a connectionless protocol that provides extensibility for host and subnet addressing, routing, security, fragmentation and reassembly, and as far as QoS is concerned a method to differentiate packets with information carried in the IP packet header.

Internet Protocol Security. IPSec is a framework for a set of protocols for security at the network or packet processing layer of network communication.

Internet Protocol version 4. The version of the Internet protocol that is widely used today. This version number is encoded in the first 4 bits of the IP packet header and is used to verify that the sender, receiver, and routers all agree on the precise format of the packet and the semantics of the formatted fields.

The MAC (Media Access Control) address, a unique hardware address that uniquely identifies each other of a network. The MAC address is a 12 digit Hexadecimal number, in which can contain one of the following characters "0123456789ABCDEF". For example, 00-09-A3-12-34-57.

An algorithm is used to create digital signatures. MD5 is a one-way hash function, meaning that it takes a message and converts it into a fixed string of digits, also called a message digest.
When using a one-way hash function, one can compare a calculated message digest against the message digest that is decrypted with a public key to verify that the message hasn't been tampered with. This comparison is called a "hashcheck."

Maximum Transmission Unit. The largest physical packet size, measured in bytes that a network can transmit. Any messages larger than the MTU are divided into smaller packets before being sent. Ethernet limits transfers to 1514(include Ethernet header) octets of data. Normally, you should leave this value as the default value. Change it only if the ISP is providing a MTU that is not optimal.

Network Address Translation. An Internet standard that enables a local-area network (LAN) to use one set of IP addresses for internal traffic and a second set of addresses for external traffic. A NAT box located where the LAN meets the Internet makes all necessary IP address translations.
NAT serves main purposes:
1) Provides a type of firewall by hiding internal IP addresses
2) Enables a company to use more internal IP addresses. Since they're used internally only, there's no possibility of conflict with IP addresses used by other companies and organizations.
It is proposed and described in RFC-1631 and is originally for solving the IP address depletion problem. Basically, "each NAT box has a table consisting of pairs of local IP addresses and globally unique addresses," by which the box can "translate" the local IP addresses to global address and vice versa.

Point-to-Point Protocol Over Ethernet. An IETF draft standard specifying how a computer interacts with a broadband modem (i.e. xDSL, cable, wireless, etc.) to achieve access to the high-speed data networks via a familiar PPP dialer such as !§Dial-Up Networking!‥ user interface. PPPoE supports a broad range of existing applications and service including authentication, accounting, secure access and configuration management. There are some service providers running of PPPoE today.

Point-to-Point Tunneling Protocol. It is a protocol that allows corporations to extend their own corporate network through private !§tunnels!‥ over the public Internet effectively.

A packet is the unit of data that is routed between an origin and a destination on the Internet or any other packet-switch network. When any file (e-mail message, HTML file, Graphics file, and so forth) is sent from one place to another on the Internet, the TCP/IP divides the file into "chunks" of an efficient size for routing. Each of these packets is separately numbered and includes the Internet address of the destination. The individual packets for a given file may travel different routes through the Internet. When they have all arrived, they are reassembled into the original file (by the TCP layer at the receiving end).

The ability to log onto a network from a distant location. Generally, this implies a computer, a modem, and some remote access software to connect to the network.

Routing is usually performed by a dedicated device called a router. Routing is a key feature of the Internet because it enables messages to pass from one computer to another and eventually reach the target machine. Each intermediary computer performs routing by passing along the message to the next computer. Part of this process involves analyzing a routing table to determine the best path.

Simple Network Management Protocol. SNMP is the protocol governing network management and the monitoring of network device and their functions. It is not limited to TCP/IP network.

A session is a series of interactions between two communication end points that occur during the span of a single connection. Typically, one end point requests a connection with another specified end point and if that end point replies agreeing to the connection, the end points take turns exchanging commands and data. The session begins when the connection is established at both ends and terminates when the connection is ended.

A syn-flood is a stream of packets that each initiate a new TCP session, but no follow-up packets are sent to complete the connection handshake. Target at a service port, this will usually overload the server such that it cannot respond to any real connection requests from real clients, as the server can only keep a limited number of connection slots active at any one time. A syn-flood is a class of attack known as a denial of service attack. The origin for syn-flood packets can be set to any address on the net, making location of the source of a syn-flood attack, difficult.

This feature can send real time system information on the web page or to the specified PC. If you want to receive real time system information to specified PC, you need to install syslog software. www.winsyslog.com offer trial version software.

Type of Service. A bit field in the IP packet header designed to contain values indicating how each packet should be handled in the network. This particular field has never been used much, though.

A method of bridging used in Ethernet and IEEE 802.3 networks by which frames are forwarder along one hop at a time, based on forwarding information at each hop. Transparent bridging gets its name from the fact that the bridges themselves are transparent to the end-systems.

Virtual Private Network. VPN provides a means for remote computers to securely communicating with each other across a public wide area network (WAN), such as the Internet. A VPN connection may be used to link two local area networks (LANs) or for a remote dialup user to connect to a private LAN.

A Virtual Server is defined as a service port, and all requests to this port will be redirected to the computer specified by the server IP. For example, if you have an FTP Server at 205.20.45.34 and a Web server at 205.20.45.35 in your LAN, then you need to specify the following virtual server mapping table: