DHCP

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The Dynamic Host Configuration Protocol (DHCP) is an auto configuration protocol used on IP networks and an extension of the Bootstrap Protocol. DHCP allows for computers to be configured automatically to communicate with each other over an IP network without the need for manual setup by a network administrator. The implementation of DHCP relies on a DHCP server to hand out network configuration information to DHCP-capable clients that request an IP address (and other information required or useful in communicating with other devices on an IP network). In addition to an IP address, common configuration information served over DHCP includes a default gateway, subnet mask and DNS sever(s).

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Learn how to PXE Boot both BIOS & UEFI machines with DHCP Policies and Custom Vendor Classes
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Expert Comment

by:Hyoin Wang
Comment Utility
Many Thanks.

One more question:
I also deploy BIOS x86, but the policy covers (x86 & x64).  I will set up two 'Define Vendor Classes' for x86 and x64? But ASCII, could I set as PXEClient:Arch:00000 for both?
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Expert Comment

by:Saeid Ansaripour
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Hello
this wont work if WDS and DHCP are on same server
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Configuring network clients can be a chore, especially if there are a large number of them or a lot of itinerant users. DHCP dynamically manages this process, much to the relief of users and administrators alike!
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Expert Comment

by:Jim Horn
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Nice work.  Voted Yes.
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Expert Comment

by:noci
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One note:
the DHCP server should also update the DNS server (& reverse zone) with issued addresses & names as well as remove them again when a lease expires..  (This only requires DHCP servers have update access to the DNS servers).
This is done slightly different in windows world there all systems have the right to put anything they like in the DNS. (and Not remove stale records).

One Caution but it maybe be beyond the scope of this article
Don't use multiple DHCP servers / network segment without understanding how it really works first.
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A Cisco router can be configured as a DHCP Server. There are advantages and disadvantages in making your Cisco router work as DHCP Server. Almost all the features for windows DHCP can be configured on Cisco-based DHCP server. Some of the features mentioned below at Setting IP Range, DNS, IP reservation and excluding IP address

Advantages: Best suited for satellite location or office connected through low bandwidth connectivity. Installing a Windows DHCP Server  or DHCP relay can consume the bandwidth. No addition hardware or software licensing required. Another advanthage is ease of configuration. It can be configured in two ways using the CLI (Command line interface) or SDM (Security Device Manager). SDM provide the GUI interface for your router. And the best part is that CISCO has also included debug commands in their IOS for troubleshooting.

Disadvantage: Will increase the load on the router, as it does the work of a router plus DHCP Server. But for a small network the load is negligible. Best suited for network that support 10 to 15 users.

Notice: The parts of the config/commands are open to variation (not specifically required keywords or commands).

Router> enable
Router# config t
Router(config)# ip dhcp pool LANPOOL
Router(dhcp-config)# network 192.168.1.0 255.255.255.0
Router(dhcp-config)# domain-name mycompany.com
Router(dhcp-config)# default-router 192.168.1.1
Router(dhcp-config)# dns-server 4.4.4.2
Router(dhcp-config)# 

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Ever wondered why you had to use DHCP options (dhcp opt 60, 66 or 67) in order to use PXE?
Well, you don't!
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Author Comment

by:vivigatt
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One side effect of having a PXE service (whether running on the same host as the DHCP service, thus requiring Dhcp Opt 60 to be set to PXEClient or on another host) is that you should NOT set DHCP opt 66 and 67.
When using a PXEService, dhcp options 66 and 67 are sent to the PXE clients by the PXE service itself, not by DHCP service.
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Author Comment

by:vivigatt
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Of course, if your clients and servers are not on the same subnets, you need to set some kind of dhcp-relay (aka ip-helper or dhcp-forwarder) so that the dhcp broadcasts sent by your PXE clients are forwarded to the dhcp server on another subnet.
If your PXE server is not your dhcp server and is not in the same subnet as the PXE clients, then, in addition not to have any dhcp option 60 set to "PXEClient", you also must add the IP address of the PXE server to the list of IP addresses that get the dhcp broadcasts. In the Cisco world, it means adding the address of the PXE server to  "ip-helper" addresses on your routers or (Layer 3) switches. In that case, you would have both the DHCP server and PXE server(s) in ip-helper list of addresses
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DHCP

10K

Solutions

14K

Contributors

The Dynamic Host Configuration Protocol (DHCP) is an auto configuration protocol used on IP networks and an extension of the Bootstrap Protocol. DHCP allows for computers to be configured automatically to communicate with each other over an IP network without the need for manual setup by a network administrator. The implementation of DHCP relies on a DHCP server to hand out network configuration information to DHCP-capable clients that request an IP address (and other information required or useful in communicating with other devices on an IP network). In addition to an IP address, common configuration information served over DHCP includes a default gateway, subnet mask and DNS sever(s).