PXE-E51 NO DHCP or PROXY DHCP offer were received

Question

HI Everyone,

Hope this finds all in their best health.

I am having a situation where I am having a difficulty to PXE boot a client on a newly setup deployment center and below is the scenario :

We have set up the IP helper on switches for PXE boot and our network guys said it is working absolutely fine.
From the DHCP side, we have disabled the scope option 60, 66, 67 considering that is supposed to be taken care of by IP helper.
We have added the VLAN ranges as the scope in our DHCP server.

Note: Our clients that needs to pxe boot, WDS server, and DHCP server are all located on a different network.

Whenever we PXE boot we get the error "PXE-E51 NO DHCP or PROXY DHCP offer were received ".

Hope someone's experience can help me out to confirm how to fix this or am I doing or missing something?

Regards,
Shashi Dubey

Answer 1

Hi，

Thanks for your reply.

==>In IP helper should it contain the request for both the PXE server and the DHCP server? Means should it sends its broadcast to both of them?
Yes, it should contain the request for both the PXE server and the DHCP server. After disabled scope option 60,66, and 67, based on my experience, there are no other special settings for DHCP.

Generally, a client computer boots from the network by using the PXE protocol according to the following process, which involves three parties (the DHCP server, the PXE server, and the client):

1.The client computer broadcasts a DHCP packet that asks for the address of the DHCP and PXE servers.
2.The DHCP server responds, sending a broadcast packet that tells the client it is an address server.
3.The PXE server responds to the client and reports that it's a boot server.
4.The client sends a request to the DHCP server to ask for the IP address.
5.The DHCP server sends the IP address to the client.
6.The client sends a request to the PXE server to ask for the path to the Network Boot Program (NBP).
7.The PXE server responds, sending the NBP path.
8.The client downloads and runs the NBP.

After this process, the basic PXE boot is completed, but there will be additional interaction between the client and the PXE server. This is controlled by the NBP implementation.

Best regards,
Simon

Answer 2

Have you reviewed the smspxe.log on the distribution point?

Answer 3

Hi,

Thank you for coming Microsoft MECM Q&A forum.

1.IP Helpers must be configured on the routers if any of the DHCP server, the client computer, or the Configuration Manager server that is running WDS and the PXE-enabled DP are on separate subnets or VLANs. IP Helpers are necessary because the PXE request that is generated by the client computer is a broadcast that doesn't travel outside the local subnet or VLAN. If the DHCP server or the WDS/PXE-enabled DP aren't on the same subnet or VLAN as the client computer, they will not see or hear the PXE request broadcast from the client. Therefore, the servers will not respond to the PXE request.

2.The routers have to be able to route the client requests from the network of the client to the network of the DHCP server. One such simple router rule is the IP helper. The helper just tells the router to forward the DHCP requests to the known IP address of the DHP server.

3.For PXE requests, you just need to configure the routers to forward the client request to the PXE server, just like you do with the DHCP server. Locate your router, find the DHCP IP helper entry, and add another entry that looks exactly like the first one but uses the IP address of the PXE server.

For more detailed information, please refer to:
How to boot from a PXE server that's on a different network
You want to PXE Boot? Don't use DHCP Options.

Thanks for your time.

Best regards,
Simon
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