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The Differences Between Hubs, Switches, and Routers on the Network The functions of a router, hub and a switch are all quite different from one another, even if at times they are all integrated into a single  device . Let's start with the hub and the switch since these two devices have similar roles on the network. Each serves as a central connection for all of your network equipment and handles a data type known as frames. Frames carry your data. When a frame is received, it is amplified and then transmitted on to the port of the destination PC. The big difference between these two devices is in the method in which frames are being delivered. In a hub, a frame is passed along or "broadcast" to every one of its ports. It doesn't matter that the frame is only destined for one port. The hub has no way of distinguishing which port a frame should be sent to. Passing it along to every port ensures that it will reach its intended destination. This places a lot o...

IIS 6.0 provides a redesigned World Wide Web Publishing Service (WWW service) architecture that can help you achieve better performance, reliability, scalability, and security for your Web sites, whether they run on a single server running IIS or on multiple servers. IIS 6.0 runs a server in one of two distinct request processing models, called application isolation modes. Application isolation is the separation of applications by process boundaries that prevents one application or Web site from affecting another and reduces the time that you spend restarting services to correct problems related to applications. In IIS 6.0, application isolation is configured differently for each of the two IIS application isolation modes. Both modes rely on theHTTP protocol stack (also referred to as HTTP.sys) to receive Hypertext Transfer Protocol (HTTP) requests from the Internet and return responses. HTTP.sys resides in kernel mode, where operating system code, such as device drivers, runs. HT...

Installation of ESXi 4.1 

Windows server 2008 two node clustering -part 1 Windows server 2008 two node clustering -part 2 Cluster failback policies (Speech in Hindi language)

Internet Protocol security (IPsec) uses cryptographic security services to protect communications over Internet Protocol (IP) networks. IPsec supports network-level peer authentication,such as secure the data sent between two computers, such as an application server and a database server. IPSec is completely transparent to applications because encryption, integrity and authentication services are implemented at the transport level. Applications continue to communicate with one another in the normal manner using TCP and UDP ports. When two computers (peers) use IPsec to communicate, they create two kinds of security associations. In the first, called main mode or phase one, the peers mutually authenticate themselves to each other, thus establishing trust between the computers. In the second, called quick mode or phase two, the peers will negotiate the particulars of the security association, including how they will digitally sign and encrypt traffic between them. The Internet Key ...

DHCP Command for showing dhcp server address authorized for the client ipconfig /showclassid adapter DHCP RELAY AGENT The DHCP Relay Agent component is a Bootstrap Protocol (BOOTP) relay agent that relays Dynamic Host Configuration Protocol (DHCP) messages between DHCP clients and DHCP servers on different IP networks. To add the DHCP Relay Agent Open Routing and Remote Access. In the console tree, click General. Where? Routing and Remote Access/server name/IP Routing/General Right-click General, and then click New Routing Protocol. In the Select Routing Protocol dialog box, click DHCP Relay Agent, and then click OK. DHCP uses a client-server model where one or more servers (DHCP servers) allocate IP addresses and other optional configuration parameters to clients (hosts) upon client bootup. These configuration parameters are leased by the server to the client for some specified amount of time. When a host boots up, the TCP/IP stack in the host transmits a...

How can I transfer some or all of the FSMO Roles from one DC to another? Windows 2000/2003 Active Directory domains utilize a Single Operation Master method called FSMO (Flexible Single Master Operation), as described in  Understanding FSMO Roles in Active Directory . In most cases an administrator can keep the FSMO role holders (all 5 of them) in the same spot (or actually, on the same DC) as has been configured by the Active Directory installation process. However, there are scenarios where an administrator would want to move one or more of the FSMO roles from the default holder DC to a different DC. Moving the FSMO roles while both the original FSMO role holder and the future FSMO role holder are online and operational is called Transferring, and is described in this article. The transfer of an FSMO role is the suggested form of moving a FSMO role between domain controllers and can be initiated by the administrator or by demoting a domain controller. However, the tran...

How can I forcibly transfer (seize) some or all of the FSMO Roles from one DC to another? Windows 2000/2003 Active Directory domains utilize a Single Operation Master method called FSMO (Flexible Single Master Operation), as described in  Understanding FSMO Roles in Active Directory . The five FSMO roles are: Schema master - Forest-wide and one per forest. Domain naming master - Forest-wide and one per forest. RID master - Domain-specific and one for each domain. PDC - PDC Emulator is domain-specific and one for each domain. Infrastructure master - Domain-specific and one for each domain. In most cases an administrator can keep the FSMO role holders (all 5 of them) in the same spot (or actually, on the same DC) as has been configured by the Active Directory installation process. However, there are scenarios where an administrator would want to move one or more of the FSMO roles from the default holder DC to a different DC. Moving the FSMO roles while both the orig...

GPC The Group Policy Container (GPC) is the portion of a GPO stored in Active Directory that resides on each domain controller in the domain. The GPC is responsible for keeping references to Client Side Extensions (CSEs), the path to the GPT, paths to software installation packages, and other referential aspects of the GPO. GPMC- group policy management console GPT- group policy template

Types of backup The Backup utility supports five methods of backing up data on your computer or network. Copy backup A copy backup copies all selected files but does not mark each file as having been backed up (in other words, the archive attribute is not cleared). Copying is useful if you want to back up files between normal and incremental backups because copying does not affect these other backup operations. Daily backup A daily backup copies all selected files that have been modified the day the daily backup is performed. The backed-up files are not marked as having been backed up (in other words, the archive attribute is not cleared). Differential backup A differential backup copies files created or changed since the last normal or incremental backup. It does not mark files as having been backed up (in other words, the archive attribute is not cleared). If you are performing a combination of normal and differential backups, restoring files and folders r...

 Round Robin Round Robin is a method of managing server (web, ftp, mail etc.) congestion by distributing connection load across multiple servers containing identical content.   Round robin works on a rotating basis in that one record is handed out, then moves to the back of the list; the next record is handed out, then it moves to the end of the list; and so on, depending on the number of servers being used. This works in a looping fashion. Let's say a company has one domain name and with identical web pages residing on three separate web servers with three different IP addresses. When one user accesses the home page she will be sent to the first IP address. The second user who accesses the home page will be sent to the next IP address, and the third user will be sent to the third IP address. In each case, once the IP address is given out, it goes to the end of the list. The fourth user, therefore, will be sent to the first IP address and so forth. Round Ro...

SOA-Records (Start of authority) A  zone  contains exactly one SOA-record, which holds the following properties for the zone: • Name of primary DNS server The host name of the primary DNS server for the zone. The zone should contain a matching  NS-record . NOTE: For dynamic updates from Windows clients and Active Directory to work correctly, it is important that this contains the correct host name for the primary DNS server for the zone, and also that an A-record exists for this name pointing to the correct IP address. • E-mail address of responsible person The e-mail address of the person responsible for the zone. The standard for this is the "hostmaster" alias - such as "hostmaster@example.com". • Serial number  (see  Zone Transfers ) Used by secondary DNS servers to check if the zone has changed. If the serial number is higher than what the secondary server has, a  zone transfer  will be initiated. Th...