What is computer networkingComputer networking means sharing of data &resources between two or more computer with acommunication between them. The communicationmedium can be through wires, radio waves, leased line,infra-red, optical fiber etc.The main purpose of networking is sharing of data &resources.
Disadvantage of Networking If fault occur in the server then all the clients are failed to access softwares from server. Network fault can cause lose of Data & resources. System open to hackers. User work dependent up on network.
Advantage of Networking Networking Enables: Information Sharing Centralized Administration and Support Hardware and Software Sharing 5
Networking Devices NIC (Network Interface Card) :- A card installed in a computer that unable the computer to communicate a network. All NIC implement a networking standards called Ethernet Every client & server must have a network interface card in order to be a part of network. Cable:- computers in a network are physically connected to each other using cables. Hub/Switch:- Network cables usually does not connect computer directly to each other. Instead of this, Each computer connected by a cable to a device known as hub or switch. The hub or switch connect rest of the network. Each switch contain certain no of port typically 8,16,24 etc. Network software:- Typically server computer use a special software in order to function efficiently & the client computer needs to have their setting configuration in order to access to the network. Network software is used to efficiently shar information.
Modem:- modem is the combination of two word modulation & demodulation. Modem is a device which convert analog signal to digital signal & vice versa. Router:- A router is a device that forwards data packets along networks. The router used to connect two or more networks & uses multiple paths to send & receive data. sometimes router is also called gateway. Access point:- Access point act as an interface cable network & wireless device. We can also connect nodes(computer) to a access point. Repeater:- Repeaters are used maintain the strength of the signal constant. Hub, Switchs, routers are also acts as a repeater.
Difference Between Switch & Hub Hub Switch It is manageable. It is not manageable. It works on the 1st layer of It works on the 2nd layer of OSI reference model. OSI reference model. Collision detection is turned Collision detection is not on. turned on. Operates on half Duplex Operates on full duplex mode. mode.
Different Modes of Communication Unicast:-one sender one receiver Multicast:- one sender multiple devices are the receiver but not all Broadcast:-One sender all other devices are receiver.
CSMA/CDCarrier Sense Multiple Access With Collisiondetection(CSMA/CD) is a protocol that is implemented in bustopology. It is divided into three part:- Multiple Access:-Multiple access refers to the fact that in bus system. EachStation has access to the common cable. Carrier Sense:-It refer to the fact that each station listen to see if no otherstation are transmitting before sending. Collision Detection:-It refers to the principal of listening if other station aretransmitting While we are transmitting.
The OSI (Open SystemsInterconnection) Data ModelISO standard for computer networks design and functioning.Involves at least 7 layers, each playing a specific role when applications are communicating over the network.
OSI Layer7. Application layer6. Presentation5. Session layer4. Transport layer3. Network layer2. Data-link layer1. Physical layer
Physical layer:- It ensures a safe and efficient travel of data; consists of electronic circuits for data transmission etc. The physical layer defines the electrical, mechanical specification for maintaining, activating, deactivating physical link between end system.Data link layer:- It is in charge of data encapsulation under the form of packets. The data link layer defines how data is formatted for transmission how access to the network is control.
Network layer:- It is in charge of packets transmission from a source A to destination B. Network layer provides connectivity &path selection between two communicating host system that might be located on two different network.Transport layer:- It is in charge of the delivery of packets from a source A to a destination B. The transport layer segments data packets from the sending host system & reassemble the data in a data stream on the receiving host system.Session layer:- It is in charge of the management of network access. The session layer establish, manages session between two communicating host system.
Presentation layer:- It determines the format of the data transmitted to applications, data compressing decompressing, encrypting etc. The presentation layer ensures the information that the application layer of one system sends out is readable by the application layer of another system.Application layer:- It contains the applications which are used by the end user, such as Java, Word etc. It provides network services to user application. It does not provide services to any other OSI layer.
SwitchNetwork Interface Card hub Router Access point modem
Repeaters and Hubs Repeater Transmits data to all connected computers Repeater Hub Transmits data to all connected computers in a star topology Hub
CablingThe two most popular types of network cabling aretwisted-pair (also known as 10BaseT) and thin coax(also known as 10Base2) & Optical Fiber. 10BaseTcabling looks like ordinary telephone wire, except thatit has 8 wires inside instead of 4. Thin coax looks likethe copper coaxial cable.
10baseTIn this type of cabling wires are twisted to each other. This help to reduce the electromagnetic induction. When 10BaseT cabling is used, a strand of cabling is inserted between each computer and a hub. If you have 5 computers, youll need 5 cables. Each cable cannot exceed 325 feet in length. Because the cables from all of the PCs converge at a common point, a 10BaseT network forms a star configuration. RJ45 connectors are used in this type of cabling.
10Base210BASE2 coax cables had a maximum length of 185 meters(607 ft). The maximum practical number of nodes that canbe connected to a 10BASE2 segment is limited to 30. In a10BASE2 network. The geometric design that is formedwhen thin coax cabling is used is called a linear orbackbone configuration. The reason for this is that thincoax is always arranged in a straight line of PCs, hubs, orother devices. Thin coax networks always requiretermination. In a 10BASE2 network, each segment of cableis connected to the transceiver (which is usually built intothe network adaptor) using a BNC T-connector, with onesegment connected to each female connector of the T.
Optical Fiber CableAn optical fiber (or optical fibre) is a flexible,transparent fiber made of glass (silica) or plastic,slightly thicker than a human hair. Optical fiber can beused as a medium for telecommunicationand computer networking because it is flexible andcan be bundled as cables. It is especially advantageousfor long-distance communications. The mostcommonly used fiber optic cable is a multi-mode fibercable (MMF) with a 62.5 micron fiber optic core .Single-mode fiber, another kind of cabling, is moreefficient than multi-mode, but far more expensive.Maximum length is up to 25 km & speed is up to 2 gb.
Network ModelsPeer-to-Peer - A peer to peer network is one in which there is no dedicated server and every computer acts as both a client and a server. This is a good networking solution when there are 10 or less users .Client/Server –This type of network is designed to support a large Number of users and uses dedicated server(s) to accomplish this. Clients log on to the server(s) in order to run applications or obtain files.
Types of networksLocal Area Network(LAN):-A local area network (LAN) is a computer network that spans a relatively small area, such as a single office or office building, and typically offers high-speed communications.Metropolitan Area Networking(MAN):- A MAN is a computer network that usually spans with in a large campus or a city. A MAN usually interconnect no of LANsWide Area Networking(WAN):- A wide are a network (WAN) computer network that spans a relatively large geographical area. Computers connected to a wide-area network are often connected through public networks, such as the telephone system, leased lines (ISDN), satellite, microwave, or other connection method.
Wireless Local Area Network(WLAN):-A communications network that provides connectivity towireless devices within a limited geographic area. "Wi-Fi" isuniversal standard for wireless networks and is the wirelessequivalent of wired Ethernet networks.Storage Area Network(SAN) :-A SAN is a network of storage devices that can be accessedby multiple computers. Each computer on the network canaccess hard drives in the SAN as if they were local disksconnected directly to the computer. This allows individualhard drives to be used by multiple computers, making iteasy to share information between different machines.personal area network(PAN):-A personal area network(PAN) is a computer networkorganized around an individual person. Personal areanetworks typically involve a mobile computer, a cellphone . You can use these networks to transfer filesincluding email and calendar appointments, digitalphotos and music. typically within 10 meters or 33 feed).
Networking TypeLocal AreaNetworkWide Area Network 33
Topology In computer networking topology refers to the layput or design of connected devices. Physical Topology:- It refers to the physical design of the network including the devices, location & cable installation. Logical Topology:-It refers to the fact that how data actually transfers in a network as opposed to its design.
Different Types of Topologies Bus Topology Star Topology Ring Topology Mesh Topology Tree Topology Hybrid Topology
Bus Topology All the nodes (file server, workstations, and peripherals) on a bus topology are connected by one single cable. A bus topology consists of a main run of cable with a terminator at each end. All nodes (file server, workstations, and peripherals) are connected to the linear cable. Popular on LANs because they are inexpensive and easy to install.
Bus TopologyAdvantages of Bus Topology It is Cheap, easy to handle and implement. Require less cable It is best suited for small networks.Disadvantages of Bus Topology The cable length is limited. This limits the number of stations that can be connected. This network topology can perform well only for a limited number of nodes.
Ring Topology In a ring network, every device has exactly two neighbours for communication purposes. All messages travel through a ring in the same direction. A failure in any cable or device breaks the loop and can take down the entire network. To implement a ring network we use the Token Ring technology. A token, or small data packet, is continuously passed around the network. When a device needs to transmit, it reserves the token for the next trip around, then attaches its data packet to it.
Ring TopologyAdvantage of Ring Topology Cable faults are easily located, making troubleshooting easier. Ring networks are moderately easy to install Easier to Mange than a Bus NetworkDisadvantages of Ring Topology The failure of a single node of the network can cause the entire network to fail. A single break in the cable can disrupt the entire network.
Star Topology In a star network, each node (file server, workstations, and peripherals) is connected to a central device called a hub. The hub takes a signal that comes from any node and passes it along to all the other nodes in the network. Data on a star network passes through the hub, switch, or concentrator before continuing to its destination. The hub, switch, or concentrator manages and controls all functions of the network. The star topology reduces the chance of network failure by connecting all of the systems to a central node.
Star TopologyAdvantages of Star Topology Easy to manage Easy to locate problems (cable/workstations) Easier to expand than a bus or ring topology. Easy to install and wire. Easy to detect faults and to remove parts.Disadvantages of Star Topology Requires more cable length than a linear topology. If the hub or concentrator fails, nodes attached are disabled. More expensive
Tree Topology A tree topology (hierarchical topology) can be viewed as a collection of star networks arranged in a hierarchy. Tree Topology is also called the combination of bus topology & star Topology This is particularly helpful for colleges, universities and schools so that each of the connect to the big network in some way.
Tree TopologyAdvantages of a Tree Topology Point-to-point wiring for individual segments. All the computers have access to the larger and their immediate networks.Disadvantages of a Tree Topology Overall length of each segment is limited by the type of cabling used. If the backbone line breaks, the entire segment goes down. More difficult to configure and wire than other topologies
Mesh Topology In this topology, each node is connected to every other node in the network. Implementing the mesh topology is expensive and difficult. In this type of network, each node may send message to destination through multiple paths. While the data is travelling on the Mesh Network it is automatically configured to reach the destination by taking the shortest route which means the least number of hops.
Mesh TopologyAdvantage of Mesh Topology No traffic problem as there are dedicated links. It has multiple links, so if one route is blocked then other routes can be used for data communication. Points to point links make fault identification easy.Disadvantage of Mesh Topology There is mesh of wiring which can be difficult to manage. Installation is complex as each node is connected to every node. Cabling cost is high.
Hybrid Topology A combination of any two or more network topologies. A hybrid topology always accrues when two different basic network topologies are connected. It is a mixture of above mentioned topologies. Usually, a central computer is attached with sub- controllers which in turn participate in a variety of topologies
Hybrid TopologyAdvantages of a Hybrid Topology It is extremely flexible. It is very reliable.Disadvantages of a Hybrid Topology Expensive
IP Address Internet Protocol Address (or IP Address) is an uniqueaddress that computing devices use to identify itself andcommunicate with other devices in the Internet Protocolnetwork. Any device connected to the IP network musthave an unique IP address within its network.IP address is a 32 bit number that is used to uniquelyidentify a computer on a network.
Subnet MaskAn IP address has two components, the network address and thehost address. A subnet mask separates the IP address into thenetwork and host addresses (<network><host>). A Subnet maskis a 32-bit number that masks an IP address, and divides the IPaddress into network address and host address. Subnet Mask ismade by setting network bits to all "1"s and setting host bits toall "0"s. Within a given network, two host addresses are reservedfor special purpose. The "0" address is assigned a networkaddress and "255" is assigned to a broadcast address, and theycannot be assigned to a host.
Default GatewayComputer can communicate directly with the othercomputer on the same network. The only way tocommunicate with a computer on the differentnetwork is through a router(internetworking). Thedefault gateway represents the IP address of the routerthat is used to communicate outside of its network.
IP Address rangesClass-A(1-126):-Example:- 184.108.40.206 (IP address) 255.0.0.0 (Subnet mask)Binary value of subnet mask 11111111.00000000.00000000.00000000Total no of host=2^n=2^24=16777216Total no of valid host=2^n-2=16777214n=Total no of Host bit1 represents for network bits & 0 represents for Host bits
IP Address rangesClass-B(128-191):-Example:- 220.127.116.11(IP address) 255.255.0.0 (Subnet mask)Binary value of subnet mask 11111111.11111111.00000000.00000000Total no of host=2^n=2^16=65536Total no of valid host=2^n-2=65534n=Total no of Host bit1 represents for network bits & 0 represents for host bits
IP Address rangesClass-C(192-223):-Example:- 192.0.0.1(IP address) 255.255.255.0 (Subnet mask)Binary value of subnet mask 11111111.11111111.11111111.00000000Total no of host=2^n=2^8=256Total no of valid host=2^n-2=254n=Total no of Host bit1 represents for network bits & 0 represents for host bits
private IP addresses The Internet Assigned Numbers Authority (IANA) has reserved the following three blocks of the IP address space for private local networks:- 10.0.0.0 - 10.255.255.255 172.16.0.0 - 172.31.255.255 192.168.0.0 - 192.168.255.255
Public IP address An IP address is considered public if the IP number is valid and falls outside any of the IP address ranges reserved for private uses by Internet standards groups. All the computer connected to the internet must have unique IP address other than the private IP address. The IP address which is used in publicly for example internet & we have to pay money for that to the service provider.
Other reserved IP address 127.0.0.0-127.255.255.255 is reserved for diagnostic & testing purpose. IP addresses in the range of 169.254.0.0 - 169.254.255.255 are reserved for Automatic Private IP Addressing.
Setting the IP address Click Start > Control Panel. On the control panel, double-click Network Connections. Right-click Local Area Connection. Click Properties. Select Internet Protocol (TCP/IP), and then click Properties. Select Use the Following IP Address. Specify the IP address, Subnet mask, and Default gateway (If available) Click OK on the Local Area Connection Properties window.
Intranet & Extranet & Internet If the Network is spans with in a office building then it is called intranet. If two different networks are connected through the internet it is called extranet. Interconnection of many Computer networks is called Internet. It is a international Computer network.
Intranet & ExtranetIntranet Internet Internet Extranet Extranet
Uniform Resource Locator (URL) It is used to locate the resource in the network. URL (http://example.microsoft.com/tutorial/default.h tml) Protocol used (http://) DNS address (example.microsoft.com) Path on the server (/tutorial/default.html
Networking Protocols Protocol:- A set of rules or guidelines that are used in networking is called protocol. Some of the networking protocols are:- TCP/IP:- It is combination of two protocols one is TCP another is IP. TCP is the connection oriented reliable protocol. It is responsible for breaking the messages into segments & reassembling them at the destination station, resending any thing that is not received. The internet protocol handles the address part of the packets so that it gets to the right destination.
ICMP( Internet Control Message protocol):- It is a networking protocol that is used by the operating system of network computer to send error message. Example:- Destination host unreachable Pop3(post Office Protocol) , IAMP( Internet Control Message Protocol) & SMTP(Simple Mail transfer Protocol):- These protocols are used for email retrieval virtually in the network. Telnet( terminal Emulation):- It is a protocol used for remotely accessing the computer of the another network.
ARP - provides IP-address to MAC address resolution for IP packets. A MAC address is your computers unique hardware number and appears in the form 00- A0-F1-27-64-E1 (for example). FTP - File transfer protocol is used for transferring files between remote systems. Must resolve host name to IP address to establish communication HTTP - The Hypertext Transfer Protocol is the set of rules for exchanging files (text, graphic images, sound, video, and other multimedia files) on the World Wide Web. It is the protocol controlling the transfer and addressing of HTTP requests and responses.
Internet protocol suite The Internet protocol suite is the set of communications protocols used for the Internetand similar networks, and generally the most popular protocol stack for wide area networks. It is commonly known as TCP/IP, because of its most important protocols: Transmission Control Protocol (TCP) and Internet Protocol(IP), which were the first networking protocols defined in this standard. TCP/IP provides end-to-end connectivity specifying how data should be formatted, addressed, transmitted, routed and received at the destination. It has four abstraction layers, each with its own protocols.
The layers are:1. The link layer (commonly Ethernet) contains communication technologies for alocal network.2. The internet layer (IP) connects local networks, thus establishing internetworking.3. The transport layer (TCP) handles host-to-host communication.4. The application layer (for example HTTP)
FirewallFirewall is any hardware or software that is designatedto prevent the unwanted networking traffic.Firewall can block the information entering to &getting out from the network.
Firewall AuthorizedLAN UserLAN Internet FirewallLAN Unauthorized User
NetMeetingNetMeeting provides people around the world with anew way of communicating. Users can work togetheron virtually any Windows-based application, exchangeor mark up graphics on an electronicwhiteboard, transfer files, or use the text-based chatprogram. To install Net meeting goes to star then runtype conf & then ok
IIS( Internet Information Service)IIS is web server software that providesintegrated, reliable, secure, and scalable software forcreating and managing internal corporate websites andexternal websites on the internet. IIS is not installedby default.
Creating IIS server Create a folder on a drive. Under this folder create a text file & write down something. Then rename the file with .html extension name. Go to IIS from start=> programs=>Administrative tools=>IIS=>expand the on computer name & then right click on website=>new=>specify the description of website =>next=>next=>browse the .html file path=> then click on finish. Then right click on website you created =>properties=>documents=>click on add=>give the html file name=>ok=>click on move up=>apply=>ok On the client side to access the website go to internet explorer type http://IP Address or DNS name
DHCP DHCP ( Dynamic Host Configuration protocol). DHCP is a protocol used to assign the IP address automatically. In a large corporate where the no of computers are more, it is difficult to assign the IP addresses automatically. That’s why we are using DHCP server to assign the IP addresses automatically DHCP releases & renews the IP addresses as devices leave & rejoin the network.
How A DHCP client get IP address from DHCP server
Advantage Of DHCPDHCP reduce the effort of administrator.Reduce the time of providing IP address.Reduce the conflict in networkingThere is no need to assign IP addresses to eachcomputer manually.
Disadvantage Of DHCP When a client location is change or another computer is connect in the place of that computer. In that case the IP address is changed.
Install DHCP server service on Windows Server 2003 Insert the Windows server 2003 CD Go to Start > Control Panel > Add or Remove Programs . When the Add or Remove Programs window launches, click Add/Remove Windows Components in the left pane. When the Windows Components Wizard comes up, scroll down and highlight Networking Services and then click the Details button. When the Networking Services window comes up, place a check mark next to Dynamic Host Configuration Protocol (DHCP) and click OK and OK again.
Configure DHCP on Windows Server 2003 Start > Administrative Tools > DHCP Right-click the server node in the left pane and choose New Scope . This will launch the New Scope Wizard. On the New Scope Wizard, click Next Specify a scope name and scope description. Specify an IP address range and subnet mask. For the Start IP address enter 192.168.0.1, for the End IP address enter192.168.0.254 . Finally, specify a subnet mask of 255.255.255.0 and click Next.
Specify IP addresses to exclude from assignment. click Add , and then click Next. The IP address of DHCP server should be in the exclude List Specify the lease duration for the scope. Verify that Days is 8 and click Next. Configure DHCP Options. Make sure “ Yes, I want to configure these settings now ” is selected and click Next to begin configuring DHCP options. Specify the router IP address and then click Next . If the router is available. Configure domain name and DNS servers.(If available) Configure WINS servers. On the next screen(If available) Finally, the wizard asks whether you want to activate the scope.
DNS(Domain Name System) Every network requires a mechanism to resolve computer names to Internet Protocol (IP) addresses. DNS is a mechanism for converting computer name to IP address also IP address to computer name. It works on two Zones. These are forward look up zone & reverse Look up zone. Forward look up zone convert computer name to IP address. Reverse look up zone convert IP address to computer name.
Installing DNS Insert the CD of Windows server 2003. Click Start, click Control Panel, and then click Add or Remove Programs. Click Add/Remove Windows Components. select the Networking Services check box, and then click Details. In Subcomponents of Networking Services, select the Domain Name System (DNS) check box, click OK, and then click Next.
Configuring DNS Start-Programs-Administrative Tools Then select DNS Expand the computer name. Right click on Forward kook up zone Select new zone Then click on Next-Next-Next Then Specify the zone Name With a .com extention name. Click on Next &Then finish.
Domain Controller A domain controller is a server that is running a version of the Windows Server operating system and has Active Directory Services installed. In Windows Server 2003 and Microsoft Windows 2000 Server, the directory service is named Active Directory. Active Directory serve as a central location for administration & security. A Microsoft active directory, in simple terms, is like a telephone book that organizes within it all of the computers and people that have been entered into it. To install Active directory services Go to Start-run type dcpromo.
Benefits of a DomainOrganized Easy Location of ParisObjects Information Sales Repair User1 Computer1 User2 Printer1 Delegated Authority
Features of a Domain Single Logon Unauthorized client can not log on to the domainCentralized Management Scalability 94
Backup Domain Controller Backup Domain Controller (BDC) is a computer that has a copy of the user accounts database. Unlike the accounts database on the Primary Domain Controller (PDC), the BDC database is a read only copy. When changes are made to the master accounts database on the PDC, the PDC pushes the updates down to the BDCs Most domains will have at least one BDC, often there are several BDCs in a domain. These additional domain controllers exist to provide fault tolerance. If the PDC fails, then it can be replaced by a BDC.
Child Domain Controller For DNS and Active Directory, a domain located in the namespace tree directly beneath another domain (the parent domain). For example, example.microsoft.com would be a child domain of the parent domain microsoft.com. Also known as a sub domain. A child domain is a member domain of a Windows Active Directory directory service but is not the root domain of that Active Directory. The main purpose of child domain is load balancing.
Domain, Tree & Forest A domain is the core administrative unit of the Windows Server 2003 directory service. However, an enterprise may have more than one domain in its Active Directory. A tree contain multiple domains with contiguous DNS name space. A forest is the combination of multiple trees.
Domain Naming Forest Mass.com Treemcse.com ccna.com Tree Tree microsoft.com example.microsoft.com sp.microsoft.com Domain Domain 98
Remote Desktop Remote Desktop allows you to access your computer from a remote location. The Remote Desktop Connection client software (for the computer from which you want to connect) is installed by default on all computers running Windows 7, Vista, or XP. For using remote desktop connection. The remote desktop connection must be enabled in the host computer.
Enable the Remote Desktopfeature on your host computer1. From the Start menu, select Control Panel (or Settings, and then Control Panel). Double-click System.2. In Windows 7 and Vista, click Remote settings. In the "Remote Desktop" section, select one of the two options to allow connections from other computers. In Windows XP, select the Remote tab. Select Allow users to connect remotely to this computer.3. To choose which users will have remote access, in 7 and Vista, click Select Users... or in XP, click Select Remote Users... . Typically, all administrators of the computer will have access by default. Each user must have a password before you can allow remote access.4. When you are finished, click OK. Your computer will now be able to accept incoming Remote Desktop connections.
How to Get Remote Desktop Start => All Programs => Accessories => Communications, => Remote Desktop Connection Then give the IP address of the computer that you want access remotely.
Internet Connection Sharing(ICS) ICS offers a simple way to configure computers in a small home office network to share a single Internet connection. For small networks, ICS offers a cost-effective way to provide Internet access to multiple computers. The IP addresses of the computers on the network must also be in the 192.168.0.x range, and the subnet mask must always be 255.255.255.0. If network computers cannot use these addresses, ICS does not work properly. When you enable ICS, the ICS computer configures itself with the IP address 192.168.0.1 and also becomes a DHCP server for the network, so that it can provide IP addressing information to other computers.
ICS using Ccpooxy software Download CCProxy from the download center, run ccproxysetup.exe and keep clicking the "Next" button to finish the installation. Launch CCProxy on the server for Internet connection sharing. After set up proxy server with CCProxy, you can create accounts and specify the authentication type for your own proxy server in the "Account Manager" dialog box of CCProxy . There are 2 authentication types for you to select: Anonymous - please select "Permit All" for "Permit Category.
Authentication required - please select "Permit Only" for "Permit Category" and then select proper "Auth Type" as you wish. CCProxy supports several authentication types such as "IP Address", "MAC Address", "User/Password" and some combined auth types as you can see in the "Account Manager" dialog box. For Internet connection sharing, we recommend "IP Address" authentication type.
Make proxy server settings for IEon client Go to client computer and open IE properties by right clicking on Internet explorer. Select "Connections" tab, click "LAN Settings" button and open the "Local Area Network(LAN) Settings" dialog box. Check "Use a proxy server for your LAN", Fill "192.168.0.1" in "Address" and "808" in "Port" Click "OK" button in "Local Area Network (LAN) Settings" and "Internet Options" dialog boxes. Now you can browser Internet web sites in IE at the client