Resize partition in Window 7 Sometime you may have large space unused in a partition. Or may have small disk space available in the partition. In bo...
Basic Computer
How to create partition in Window
30 Dec 20180
How to create a partition in Window 7 Sometime you may create single partition during the installation of Window 7 leaving the remaining space of ...
DATA RECOVERY
30 Dec 20181
DATA RECOVERY Data recovery is the process of recovering data from secondary storage devices ( including a hard disk, USB disk, memory card etc) w...
Full Forms of Hardware and Networking Devices
30 Dec 20180
Full Form of hardware and networking devices In Comptia N+ or A+ exam, you may have a question asking for the full form. Beside exam in the netwo...
Types of Computer Ports
30 Dec 20180
Examples of computer hardware System Unit Types of Ports Types of Connectors The System Unit The System Unit houses the central processing unit, ...
Computer hardware components
30 Dec 20180
Computer hardware components Input Devices Output Devices Hardware components Input devices - accept data or commands in a form useable by compute...
Basic Networking
How to configure peer to peer workgroup network step by step Guide
05 Jan 20190
BASIC WORKGROUP NETWORKING Workgroup networking is the essence of computer networking. In this section, we have prepared a step by step practical guide fo...
NETWORK MEDIA AND TOPOLOGIES
05 Jan 20190
NETWORK MEDIA AND TOPOLOGIES If you are wondering what media and topologies refer to, it all starts in the wiring closet. Media is the cabling, and topolo...
OSI Seven Layer model
04 Jan 20190
OSI Seven Layer model Explained Layer model is a theoretical approach to describe how data is going to be transmitted over the network. There are ...
OSI LAYER MODEL
04 Jan 20190
OSI LAYER MODELS In this section, we would introduce you to internetworking. You will learn the basics of the Open Systems Interconnection (OSI) mod...
CCNA STUDY GUIDE
04 Jan 20190
CCNA STUDY GUIDE The networking industry has virtually boomed in recent years. The networking industry is highly competitive, and evolving technolog...
Advanced Networking
How To Configure DNS Domain Name
06 Jan 20190
How To Configure DNS Domain Name System In Server 2003 ADS uses Domain Name System (DNS) to locate resources on a network. Without a reliable DNS infrastr...
What is DNS Server?
06 Jan 20190
DNS Server Virtually every computer requires a mechanism to resolve the name to IP addresses. This requirement arises because IP address consists of fo...
You are here
NETWORK TECHNOLOGIES
What is Network Technologie?
How DHCP work
DHCP discovery
DHCP offer
DHCP request
DHCP acknowledgement
This section covers the different protocols used on a network. In this section, you will learn about MAC addresses, the OSI model, and the common network protocols such as TCP/IP, FTP, SMTP, and TFTP, for example. This section also covers TCP/UDP port functionality, network services such as DHCP, DNS, WINS, and SNMP. IP Addressing is also covered in this part along with understanding public and private networks, WAN technologies, remote access, and security protocols.
Computers on an IP network need some essentials information before it can communicate with other hosts. This information includes an IP address, and a default route and routing prefix. Configuring IP addressing on a large TCP/IP-based network can be a nightmare, especially if machines are moved from one network to another frequently. DHCP eliminates the manual task by a network administrator. The Dynamic Host Configuration Protocol (DHCP) can help with the workload of configuring systems on a network by assigning addresses to systems on boot-up automatically. It also provides a central database of devices that are connected to the network and eliminates duplicate resource assignments.
The DHCP server may have three methods of allocating IP-addresses:
static allocation: The DHCP server allocates an IP address based on a table with MAC address/IP address pairs, which are manually filled Only requesting clients with a MAC address listed in this table will be allocated an IP address.
dynamic allocation: A network administrator assigns a range of IP addresses to DHCP, and each client computer on the LAN is configured to request an IP address from the DHCP server during network initialization.
automatic allocation: The DHCP server permanently assigns a free IP address to a requesting client from the range defined by the administrator. This is like dynamic allocation, but the DHCP server keeps a table of past IP address assignments so that it can preferentially assign to a client the same IP address that the client previously had.
Among these three methods, static and dynamic method are the most popular implementation.
How DHCP work
DHCP provides an automated way to distribute and update IP addresses and other configuration information on a network. A DHCP server provides this information to a DHCP client through the exchange of a series of messages, known as the DHCP conversation or the DHCP transaction.
DHCP discovery
The client computers broadcast messages on the physical subnet to discover available DHCP servers. This client-computers creates a User Datagram Protocol (UDP) packet with the default broadcast destination of 255.255.255.255 or the specific subnet broadcast address if any configured.
DHCP offer
When a DHCP server receives an IP lease request from a client, it reserves an IP address for the client and extends an IP lease offer by sending a DHCPOFFER message to the client. This message contains the client's MAC address, the IP address that the server is offering, the subnet mask, the lease duration, and the IP address of the DHCP server making the offer.
DHCP request
In most companies, two DHCP servers provide fault tolerance of IP addressing if one server fails or must be taken offline for maintenance. So the client could receive DHCP offers from multiple servers, but it will accept only one DHCP offer. In response to the offer, Client requests the server. The client replies DHCP Request, unicast to the server, requesting the offered address. Based on the Transaction ID field in the request, servers are informed whose offer the client has accepted. When other DHCP servers receive this message, they withdraw any offers that they might have made to the client and return the offered address to the pool of available addresses. In some cases, DHCP request message is broadcast, instead of being unicast to a particular DHCP server, because the DHCP client has still not received an IP address. Also, this way one message can let all other DHCP servers know that another server will be supplying the IP address without missing any of the servers with a series of unicast messages.
DHCP acknowledgement
When the DHCP server receives the DHCPREQUEST message from the client, the configuration process enters its final phase. The acknowledgement phase involves sending a DHCPACK packet to the client. This packet includes the lease duration and any other configuration information that the client might have requested. At this point, the IP configuration process is completed.
No comments: