Dynamic IP assignment:IP addresses that are automatically assigned for a specific period of a
time might change.
EX: DHCP(Dynamic Host Configuration Protocol).
Static IP assignment: Address that are manually assign and do not change overtime.
DHCP:
Dynamic Host Configuration Protocol (DHCP) is a standard protocol that allows a server to dynamically distribute IP addressing and configuration information to clients. Normally the DHCP server provides the client with at least this basic information:
IP Address
Subnet Mask
Default Gateway
Other information can be provided as well, such as Domain Name Service (DNS) server addresses and Windows Internet Name Service (WINS) server addresses. The system administrator configures the DHCP server with the options that are parsed out to the client.
Advantages:
1. Decreases the admin burden.
2. Reduces IP conflict
3. Automatically we can assign DNS and Gateway.
4.centralized IP address management.
Features:
1. Exclude some addresses.
2. Static also can be apply for each and every pc by using MAC address
For obtaining IP using DHCP server it will follow the DORA process
D= Discover (Discover the server in the network)
O= Offer (Server offers IP)
R= Request (Client request IP)
A= Acknowledgement (Server gives acknowledgement)
The process between client and DHCP service is DORA process.
The transmission of DORA process is broadcasting.
Scope: Group of valid range of IP addresses which we want to assign for a system in a network.
options:1. Address pool
2. Address Lease
3. Exclusion
4. Reservation
5. Lease period
Address pool: Range of addresses which we want to apply for clients
Address Lease: The addresses which obtained from the DHCP server the PC’s will be listed in address lease.
Exclusion: The range of addresses which we want to exclude from address pool.
Reservation: Used to assign a particular address for particular client by binding MAC address as an IP Address.
Getting mac address : get mac –s sys2name or get mac \s sys2name
If DHCP client is running continuously in the network .After completion of 50% or 87.5% of its IP lease duration DHCP client will send request packet DHCP server and request IP lease duration.
Lease Period:
limited: 8 Days to 999,23hr,59sec
Unlimited: Depends upon the system, for more years.
Allocation
Reallocation
Normal operation
Renewal
Rebinding
Release
If DHCP server is not available in the network then os of DHCP client will assign an IP address automatically.which is called apipa (automatic IP address).
The range of apipa address is 169.254.0.0 to 169.254.255.255
Computerized DHCP can be available in windows server 2012,2003,2008,Linux,UNIX.
The database name of DHCP is DHCP.Mdb(media data base)
The location of DHCP.mdb is c:/windows/sys32/DHCP.Mdb
Port number of DHCP server is 67.
Port number of DHCP client is 68.
DHCP client and server communicate by using user datagram protocol(UDP).
DHCP works on Application layer.
Installation DHCP in windows server 2012:
Install DHCP.
Post-install configuration wizard, click next.
Click commit to authorize the DHCP server.
Click close complete authorization of DHCP server.
Create a scope:
Expand sys name.
Right click on IPV4.
Select new scope.
Click next.
Scope name.scope1 then next
Enter the IP address range to be leased to clients, click next
Scope range in the same network of DHCP server.
To execute IP address enter the start and end IP address, click on add, click next.
In the lease duration screen, you can increase or decrease the value click next.
Tick yes, I want to configure these options now and click next.
In router (default gateway)screen .enter the IP address of the router that will function as the default gateway for this scope clients and click add or if you don’t have a router in your network just click next.
In the domain name and DNS server screen enter the name of the parent domain and IP address of the DNS server.
click add.
Click next
In windows screen enter details of windows server just click next
Activate scope screen, select yes and click next
Finish scope.
Verification:
Change the select to obtain IP address automatically.
In cmd type ip config/release.
Then ip config /renew.
After right click on network icon
Select properties to view details.
Verify IP address leased by the DHCP service along with lease duration
DHCP reservation:
Open DHCP
Expand domain name
Expand IPV4
Expand scope
Right click on reservation
Select on new reservation.
Type reservation name and IP and mac address of client system
Tick as both
In client system
In cmd
config/release
Then ip config /renew.
DHCP server backup:
Open DHCP and right click on server name
Select backup
Then select location and click ok.
Restore:
Now delete entire scope.
Right click on server name
Select restore and select path.
Configure DHCP server fail-over
This fracture is available in windows 2012 ensuring continuous availability of DHCP service to clients
With DHCP failover, two DHCP servers share DHCP scope and lease information ,enabling one server to provide DHCP leases to DHCP clients if the other server is unavailable
Hot stand-by mode: this mode provides for DHCP service.
Load balance mode: this mode allocates DHCP client leases across service
Practical
Sys2:insatll DHCP server role on sys2 and do not authorize the server
Sys1 :open DHCP console
Expand server name
Expand IPV4
Right click on scope
Select config failover.
Introduction to DHCP failover wizard, click next
Add failover
server like (sys2.ss.com)click ok
Select the mode ,enable message authentication and enter shared next
To complete the failover,click finish
Verify summary to be successful.
Sys2 c:post installation wizard ,click next
Click commit ,to authorize the DHCP server sys2.ss.com
Verify summary and close.
Verification : DHCP console and verify the scope replicated from sys1.
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