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9. Terms-Glossary·CAT5
·DHCP
·DMZ
·DYNAMIC
·IN or INCOMING Ports
·IP
·ISP
·LAN
·MAC Address
·MTU
·NAT (Firewall)
·NIC
·OUT Port
·PPPoA
·PPPoE
·PPTP
·PUBLIC Port
·STATIC
·TCP Port(s)
·TCP/IP
·TRIGGER Port
·UDP Port(s)
·UPnP
·VPN
·WAN
·WEP?
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CAT5- Category 5 type cable. Designed with specific qualities to transmit ethernet data signals up to 100mbps
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Dynamic Host Configuration Protocol. The principal is that a device that knows nothing about its own network settings sends out a broadcast packet saying, in effect, tell me what to do. The DHCP server is listening for these packets, and responds with a packet containing the settings that device should have. A DHCP server is configured with a table of ethernet addresses, and ranges of IP addresses, and maps that describe who gets what and when. Because a constantly changing IP address can be destabilizing, the DHCP server uses the concept of a lease, to tell the device it has this IP address for only a limited time. When the lease runs out, the device tries to obtain a renewal and, possibly, gets a new IP address given to it! If the device is allocated a new IP address, it must reconfigure itself to take that feedback needed: please tell us whether windows machines can handle this or reboot.
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DMZ
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In computer networks, a DMZ (demilitarized zone) is a computer host or small network inserted as a "neutral zone" between a company's private network and the outside public network. It prevents outside users from getting direct access to a server that has company data. (The term comes from the geographic buffer zone that was set up between North Korea and South Korea following the war in the early 1950s.) A DMZ is an optional and more secure approach to a firewall and effectively acts as a proxy server as well.
In a typical DMZ configuration for a small company, a separate computer (or host in network terms) receives requests from users within the private network for access to Web sites or other companies accessible on the public network. The DMZ host then initiates sessions for these requests on the public network. However, the DMZ host is not able to initiate a session back into the private network. It can only forward packets that have already been requested.
Users of the public network outside the company can access only the DMZ host. The DMZ may typically also have the company's Web pages so these could be served to the outside world. However, the DMZ provides access to no other company data. In the event that an outside user penetrated the DMZ host's security, the Web pages might be corrupted but no other company information would be exposed. Cisco, the leading maker of routers, is one company that sells products designed for setting up a DMZ.
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DYNAMIC- Obtain an IP address from ISP automatically.
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The IN or INCOMMING port. When a TRIGGER or OUT port packet is detected, the inbound packets to the specific port numbers are allowed to pass through the firewall. See PUBLIC Port
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The Internet Protocol (IP) is the method or protocol by which data is sent from one computer to another on the Internet. Each computer (known as a host) on the Internet has at least one IP address that uniquely identifies it from all other computers on the Internet. When you send or receive data (for example, an e-mail note or a Web page), the message gets divided into little chunks called packets. Each of these packets contains both the sender's Internet address and the receiver's address. Any packet is sent first to a gateway computer that understands a small part of the Internet. The gateway computer reads the destination address and forwards the packet to an adjacent gateway that in turn reads the destination address and so forth across the Internet until one gateway recognizes the packet as belonging to a computer within its immediate neighborhood or domain. That gateway then forwards the packet directly to the computer whose address is specified.
Because a message is divided into a number of packets, each packet can, if necessary, be sent by a different route across the Internet. Packets can arrive in a different order than the order they were sent in. The Internet Protocol just delivers them. It's up to another protocol, the Transmission Control Protocol (TCP) to put them back in the right order.
IP is a connectionless protocol, which means that there is no continuing connection between the end points that are communicating. Each packet that travels through the Internet is treated as an independent unit of data without any relation to any other unit of data. (The reason the packets do get put in the right order is because of TCP, the connection-oriented protocol that keeps track of the packet sequence in a message.) In the Open Systems Interconnection (OSI) communication model, IP is in layer 3, the Networking Layer.
The most widely used version of IP today is Internet Protocol Version 4 (IPv4). However, IP Version 6 (IPv6 ) is also beginning to be supported. IPv6 provides for much longer addresses and therefore for the possibility of many more Internet users. IPv6 includes the capabilities of IPv4 and any server that can support IPv6 packets can also support IPv4 packets.
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An ISP (Internet service provider) is a company that provides individuals and other companies access to the Internet and other related services such as Web site building and virtual hosting. An ISP has the equipment and the telecommunication line access required to have a point-of-presence on the Internet for the geographic area served. The larger ISPs have their own high-speed leased lines so that they are less dependent on the telecommunication providers and can provide better service to their customers.
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LAN- Local Area Network. Your network behind a router.
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What is a MAC Address?
The unique serial number burned into Ethernet and Token Ring adapters that identify that network card from all others.
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MTU - The MTU setting controls the maximum ethernet packet size your PC will send (you did know the internet works in packets, didn't you?). Why a limit? because although larger packets can be constructed and sent, Your ISP and Internet backbone routers and equipment will chop up (fragment) any larger than their limit, then these parts are re-assembled by the target equipment before reading. This fragmentation, and re-assembly is not optimal.
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Network Address Translation - An IETF
standard that allows an organization to
present itself to the Internet with one
address. NAT converts the address of
each LAN node into one IP address for
the Internet and vice versa. It also
serves as a firewall by keeping individual
IP addresses hidden from the outside
world. Firewalls are frequently used to
prevent unauthorized Internet users
from accessing private networks
connected to the Internet. All messages
entering or leaving the intranet pass
through the firewall, which examines
each message and blocks those that do
not meet the specified security criteria.
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NIC- Network Interface Card. Usually a ethernet wired network card or a wireless network card in your computer.
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OUT- A OUT port is a out going port that is opened by a application or a game to a server or web site on the internet. See TRIGGER.
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PPPoA- Point to Point Protocol Over ATM (Asycronus Transfer Mode).
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PPPoE (Point-to-Point Protocol over Ethernet) is a specification for connecting multiple computer users on an Ethernet local area network to a remote site through common customer premises equipment, which is the telephone company's term for a modem and similar devices. PPPoE can be used to have an office or building-full of users share a common Digital Subscriber Line (DSL), cable modem, or wireless connection to the Internet. PPPoE combines the Point-to-Point Protocol (PPP ), commonly used in dialup connections, with the Ethernet protocol, which supports multiple users in a local area network. The PPP protocol information is encapsulated within an Ethernet frame.
PPPoE has the advantage that neither the telephone company nor the Internet service provider (ISP ) needs to provide any special support. Unlike dialup connections, DSL and cable modem connections are "always on." Since a number of different users are sharing the same physical connection to the remote service provider, a way is needed to keep track of which user traffic should go to and which user should be billed. PPPoE provides for each user-remote site session to learn each other's network addresses (during an initial exchange called "discovery"). Once a session is established between an individual user and the remote site (for example, an Internet service provider), the session can be monitored for billing purposes. Many apartment houses, hotels, and corporations are now providing shared Internet access over DSL lines using Ethernet and PPPoE.
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PPTP, a proposed standard sponsored by Microsoft and other companies, and Layer 2 Tunneling Protocol, proposed by Cisco Systems, are among the most likely proposals as the basis for a new Internet Engineering Task Force (IETF) standard. With PPTP, which is an extension of the Internet's Point-to-Point Protocol (PPP), any user of a PC with PPP client support is able to use an independent service provider (ISP) to connect securely to a server elsewhere in the user's company.
Point-to-Point Tunneling Protocol (PPTP) is a protocol (set of communication rules) that allows corporations to extend their own corporate network through private "tunnels" over the public Internet. Effectively, a corporation uses a wide-area network as a single large local area network. A company no longer needs to lease its own lines for wide-area communication but can securely use the public networks. This kind of interconnection is known as a virtual private network (VPN).
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PUBLIC port numbers are port numbers that are available for use by any application to use in communicating with any other application, using the Internet's Transmission Control Protocol (TCP) or the User Datagram Protocol (UDP). When one application communicates with another application at another host computer on the Internet, it specifies that application in each data transmission by using its port number. The port numbers range from 0 through 65535. See IN Port.
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STATIC- Fixed IP address usually assigned by ISP for WAN connection, or assigned by user in LAN connection.
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What are TCP ports?
Transmission Control Protocol - TCP and UDP (User Datagram Protocol) are the two transport protocols in TCP/IP.
TCP ensures that a message is sent accurately and in its entirety. However, for real-time voice and video, there is really no time or reason to correct errors, and UDP is used instead.
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TCP/IP- Transfer Control Protocol / Internet Protocol.
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TRIGGER Port. The outbound port number that the application or a game assigned first. See OUT
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What are UDP ports?
User Datagram Protocol - A protocol within the TCP/IP protocol suite that is used in place of TCP when a reliable delivery is not required. For example, UDP is used for real-time audio and video traffic where lost packets are simply ignored, because there is no time to retransmit. If UDP is used and a reliable delivery is required, packet sequence checking and error notification must be written into the applications.
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Universal Plug and Play.
Universal Plug and Play (UPnP) is a standard that uses Internet and Web protocol s to enable devices such as PCs, peripherals, intelligent appliances, and wireless devices to be plugged into a network and automatically know about each other. With UPnP, when a user plugs a device into the network, the device will configure itself, acquire a TCP/IP address, and use a discovery protocol based on the Internet's Hypertext Transfer Protocol (HTTP ) to announce its presence on the network to other devices. For instance, if you had a camera and a printer connected to the network and needed to print out a photograph, you could press a button on the camera and have the camera send a "discover" request asking if there were any printers on the network. The printer would identify itself and send its location in the form of a universal resource locator (URL).
The camera and printer would use Extensible Markup Language (XML ) to establish a common language, or "protocol negotiation", to talk to each other and determine capabilities. Once a common language was established, the camera would control the printer and print the photograph you selected. Microsoft, one of 29 companies sponsoring UPnP, hopes that UPnP will make it as easy to plug a device or appliance into a home or small business data network as it is to plug a lamp into an electrical outlet.
Universal Plug and Play is an open industry standard that Microsoft, a leading promoter of the standard, describes as "seamless proximity networking" that provides "standardization on the wire rather than in the devices," using existing Internet standards.
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A virtual private network (VPN) is a private data network that makes use of the public telecommunication infrastructure, maintaining privacy through the use of a tunneling protocol and security procedures. A virtual private network can be contrasted with a system of owned or leased lines that can only be used by one company. The idea of the VPN is to give the company the same capabilities at much lower cost by using the shared public infrastructure rather than a private one. Phone companies have provided secure shared resources for voice messages. A virtual private network makes it possible to have the same secure sharing of public resources for data. Companies today are looking at using a private virtual network for both extranets and wide-area intranets.
Using a virtual private network involves encrypting data before sending it through the public network and decrypting it at the receiving end. An additional level of security involves encrypting not only the data but also the originating and receiving network addresses. Microsoft, 3Com, and several other companies have developed the Point-to-Point Tunneling Protocol (PPTP) and Microsoft has extended Windows NT to support it. VPN software is typically installed as part of a company's firewall server.
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WAN- Wide Area Network. Usually this references refers to the internet or a geographically large private intranet riding on the public internet.
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WEP - Short for Wired Equivalent Privacy, a security protocol for wireless local area networks (WLANs) defined in the 802.11B standard. WEP is designed to provide the same level of security as that of a wired LAN. LANs are inherently more secure than WLANs because LANs are somewhat protected by the physicalities of their structure, having some or all part of the network inside a building that can be protected from unauthorized access. WLANs, which are over radio waves, do not have the same physical structure and therefore are more vulnerable to tampering. WEP aims to provide security by encrypting data over radio waves so that it is protected as it is transmitted from one end point to another. The Wired Equivalent Privacy (WEP) feature uses the RC4 PRNG algorithm developed by RSA Data Security, Inc. If your wireless base station supports MAC filtering, it is recommended that you use this feature in addition to WEP (MAC filtering is much more secure than encryption)
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