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What is DHCP reservation

Posted on 2011-02-27
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Last Modified: 2012-05-11
HI,
Can any please tell me in words what DHCP reservation is?
Is it binding the IP with a mack address?
if that what exactly is mack address



thanks
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Question by:SameerMirza
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by:santoshmotwani
ID: 34994145
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by:mrcannon
ID: 34994159
The DHCP server gives out IP addresses.  In the case of a DHCP reservation the IP address is always the same for a particular MAC address.  The MAC address is the unique hexadecimal number assigned to a particular network device.  Normally where a reservation does not exist a network device will receive a random number from a pool of IP addresses.
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by:8ubterfug3
ID: 34994169
It is a method for specifying that a certain device should always get a certain IP address. Each device on a network has a unique physical address (MAC address). You specify that a device with a certain physical address will always get the same IP address. This is a DHCP reservation
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by:JT92677
ID: 34994303
You can use DHCP on some machine on your network, but if you want to be sure that computer always gets handed the same IP address via DHCP, you can tell your router to assign the same IP address to the MAC address (Media Access Control) which is the hardware identifier (unique to every network device).

I reserve addresses on my router so I can then forward connections to a particular PORT to a particular IP address and know that the forwarded packets will always go to the expected computer.

This is done in the router, the client machines on the network don't reserve IP addresses if they use DHCP, but the router that hands out IP addresses can do this. You would need administrative access to the router, and edit the LAN clients AFTER they have been given their IP address.

Looking at the clients on the LAN, and knowing the IP address assigned to the machine you want to reserve the same address each time, it's just a matter of checking the IP address that was handed out and specifying that it should be reserved for that LAN user.

Hope this helps,

Jeff
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by:Krzysztof Pytko
ID: 34994744
Simply saying :)

Compare DHCP reservation with car parking place :)
Kr

You are always sure that your car is parked always in the same place. The same with DHCP reservation. You create IP which is always assigned to your machine :) Mostly used when you want to have "static IP" within DHCP environment (preventing set up static IP manually)

Regards,
Krzysztof
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by:crash2000
ID: 34995641
DHCP iReservation is a way of ensureing a device or workstation always gets the same IP address.
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by:SameerMirza
ID: 34995746
I dont understand what same ip address means here?
the one that we are willing to bind
or always same for every work station and then we change it?
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Krzysztof Pytko earned 167 total points
ID: 34995766
You have some IPs pool, and you want to assign static IP to one of your workstation (i.e. 192.168.0.10) But you don't want to do it manually (static configuration). Then you can create a DHCP reservation. This IP address (192.168.0.10) will always will be issued to that particular workstation (reservation is made by using workstation's MAC address). That means, your address is issued by DHCP server but has some common features of static configuration. If you sidh to change IP, you don't have to do it on workstation but only in DHCP console. Your workstation will pull new settings from there.

Krzysztof
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by:vivigatt
vivigatt earned 167 total points
ID: 34996488
DHCP can assign an IP address to a particular client "randomly", picking the IP adress in a in a pool.
For instance, you can have a pool of 10 IP addresses , starting at 192.168.1.11 and ending and 192.168.1.20.
DHCP identifies each client using a "unique identifier". Usually the MAC address (also known as Ethernet address). This is a globally unique identifier that the manufacturer of the network card used in a client assigns to said network card. It as the form: 00:11:22:33:44:55 (it can be any combination of hexadecimal figures)

If you want that the client with MAC address 00:AA:BB:CC:DD:EE always get the IP address 192.168.1.15, you can then create a DHCP reservation. Instead of picking up any free IP address in the pool, the DHCP server will then always send the IP address 192.168.1.15 when he receives a DHCP request from client with MAC address 00:AA:BB:CC:DD:EE

Hope this helps
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by:JT92677
JT92677 earned 166 total points
ID: 34997264
IP (Internet Protocol) addresses are like telephone numbers. In your area code, no two people can have the same telephone exchange and number.

What DHCP does differs from phone numbers in that every time a computer is turned on, if it's set to get it's "network number" from the DHCP server (typically a router on home Local Area Networks) it might get a different number each time depending on other computers on that network.

No two computers on your network can have the same IP, so the DHCP server assures that each machine that requests an IP address (a temporary number to use to carry out data transfers) gets a unique one.  Then, on your network, another system allows you to refer to other computers by name rather than IP number. This is what you see when you go to My Network Places and request a list of machines on your network. You are given the machine name, but the operating system also gets, and stores the name along with the number.

It's like saying you want to call Mr. Smith on the phone. Technically, all you really need to know is the name "Mr. Smith" and you ask "information" (Domain Name Service) to give you the phone number for that name, then you make your connection by calling that number. Same analogy to IP addresses. You want to talk to a machine on your network, establish a file transfer, etc., you need to select the machine from a list, and the operating system takes care of translating the name to an IP address.

If you reserve an IP address, then you can be assured that the machine will always show up at that IP address, and this simplifies some (but not all) access to that machine.

For example, if you know the IP address of a network attached storage device, you could get a list of all the network devices and select the server from the list, OR you can type in the server IP address directly in the explorer address line.

If my NAS (Network Attached Storage) address is, for example, 172.16.44.29, I could type in

\\172.16.44.29

in the address line of the my computer icon, and I would then connect directly to the NAS. I could create a shortcut to the NAS and know that every time I selected that shortcut, it would take me to that NAS. If the NAS used DHCP to get it's IP address, rather than let it get a different address each time it's rebooted, or shut down and restarted, you could inform the DHCP server (typically a router) to reserve the same address for the NAS device so that every time it is turned on, it gets the same, known, IP address, and your shortcut would still work.

Make sense?

Jeff
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Author Closing Comment

by:SameerMirza
ID: 35016932
Thanks everyone for your help
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