WDS DHCP PXE, Clients on different subnet

[danletkeman]

Hello,

 

We are having a lot of trouble trying to get pxe imaging working from our WDS server on different subnets. We have an existing Zenworking imaging setup working as of right now, but WDS is causing more issues than I care to troubleshoot. I have read blog after blog, forum post after forum post and everyone says just install it and it works! I guess we have run into some sort of problem that nobody else has.

 

Enviroment:

 

2x DC's, Server 2012 R2, both run DNS, 10.5.0.101, 10.5.0.102

 

1x DHCP Server, 2012 R2, 10.5.0.105

 

1x WDS Server, 2012 R2, 10.5.0.41

 

 

 

If I put a client on the same subnet as all of the servers it seems to work, except for the fact that it takes a while for the client to get an IP and continue to load wdsnbp.com. I would say around 20-30 seconds. In our zenworks enviroment it takes no more than 1 second to get an IP. As for the dhcp server itself, clients receive normal dhcp offers instantly. So that part is working properly.

 

 

 

Now when I try an access the WDS pxe server from a different subnet other than the one that all of the servers are on, noting that I do have the ip helper address setup on our layer 3 switch:

 

interface Vlan2025

ip address 10.200.20.1 255.255.255.0

ip helper-address 10.5.0.105

ip helper-address 10.5.0.41

 

It always says failed to receive boot file. But as I said earlier, clients in windows receive dhcp leases from 10.5.0.105 without issue.

 

Setting the client options in the DHCP server with options 66 and 67 works sortof, but we found that it was unreliable and often finicky. Like having the system repeatedly ask to press f12, and even if you did press f12 it would still ask to press f12 again.

 

So I continued to do a wirehark packet capture on the port where the device was trying to get the dhcp/pxe info from the DHCP / WDS servers. The first packet here is from the DHCP server and the second is from the WDS server.

 

Bootstrap Protocol

Message type: Boot Reply (2)

Hardware type: Ethernet (0x01)

Hardware address length: 6

Hops: 0

Transaction ID: 0xd6c565d2

Seconds elapsed: 0

Bootp flags: 0x8000 (Broadcast)

Client IP address: 0.0.0.0 (0.0.0.0)

Your (client) IP address: 10.200.20.117 (10.200.20.117)

Next server IP address: 10.5.0.105 (10.5.0.105)

Relay agent IP address: 10.200.20.1 (10.200.20.1)

Client MAC address: Hewlett-_c5:65:d2 (78:e7:d1:c5:65:d2)

Client hardware address padding: 00000000000000000000

Server host name not given

Boot file name not given

Magic cookie: DHCP

Option: (53) DHCP Message Type

Length: 1

DHCP: Offer (2)

Option: (1) Subnet Mask

Length: 4

Subnet Mask: 255.255.255.0 (255.255.255.0)

Option: (58) Renewal Time Value

Length: 4

Renewal Time Value: (21600s) 6 hours

Option: (59) Rebinding Time Value

Length: 4

Rebinding Time Value: (37800s) 10 hours, 30 minutes

Option: (51) IP Address Lease Time

Length: 4

IP Address Lease Time: (43200s) 12 hours

Option: (54) DHCP Server Identifier

Length: 4

DHCP Server Identifier: 10.5.0.105 (10.5.0.105)

Option: (3) Router

Length: 4

Router: 10.200.20.1 (10.200.20.1)

Option: (6) Domain Name Server

Length: 8

Domain Name Server: 10.5.0.101 (10.5.0.101)

Domain Name Server: 10.5.0.102 (10.5.0.102)

Option: (15) Domain Name

Length: 8

Domain Name: domain.com

Option: (255) End

Option End: 255

------------------------------------------------------------------------

 

Bootstrap Protocol

Message type: Boot Reply (2)

Hardware type: Ethernet (0x01)

Hardware address length: 6

Hops: 0

Transaction ID: 0xd2c565d2

Seconds elapsed: 4

Bootp flags: 0x8000 (Broadcast)

Client IP address: 0.0.0.0 (0.0.0.0)

Your (client) IP address: 0.0.0.0 (0.0.0.0)

Next server IP address: 10.5.0.41 (10.5.0.41)

Relay agent IP address: 10.200.20.1 (10.200.20.1)

Client MAC address: Hewlett-_c5:65:d2 (78:e7:d1:c5:65:d2)

Client hardware address padding: 00000000000000000000

Server host name: wds1.domain.com

Boot file name not given

Magic cookie: DHCP

Option: (54) DHCP Server Identifier

Length: 4

DHCP Server Identifier: 10.5.0.41 (10.5.0.41)

Option: (97) UUID/GUID-based Client Identifier

Length: 17

Client Identifier (UUID): eb8daa31-8e62-11df-bbd8-d1c565d278e7

Option: (60) Vendor class identifier

Length: 9

Vendor class identifier: PXEClient

Option: (53) DHCP Message Type

Length: 1

DHCP: Offer (2)

Option: (255) End

Option End: 255

 

 

---------------------------------------------------------------

 

What I find interesting is that the WDS server is not handing out a boot file name:

 

"Boot file name not given"

 

Could this be the reason why we receive the no boot file received error when trying to boot a client into pxe?

 

The other thing that I noticed was that the WDS server is also responding with the:

 

" Option: (60) Vendor class identifier

Length: 9

Vendor class identifier: PXEClient

 

"

 

Why would it be responding with this, when the dhcp is on a separate server. Is this option only if you have DHCP and WDS on the same server?

 

 

 

Any help would be appreciated as there has been too much time already spent on getting nowhere.

 

Thanks,

 

Dan.