DHCP on Cisco Device

[prabhu050446]

Hello Everyone,

We migrated DHCP service from Windows to Cisco Device (works perfectly fine) but our PXE imaging is broken after migration.

I was trying trial and error and found below based on our requirements.

Requirements: All devices (Microsoft Surface and HP Z840 desktops) should be able to PXE imaged.

Set Up: our imaging server (SCCM server) is on VLAN 100 and imaging clients (HP Z840 and Surfaces) are on VLAN 200. Already have IP helper on the client VLAN.

Observations:

a) If I have only dhcp option 60 PXEClient configured under cisco DHCP scope then Surface PXE imaging works but not HP Z840.

b) If I have only Option 67 with filename smsboot\x64\wdsnbp.com then Z840 work but not Surface.

No other options like 66 or combination of 60, 66 and 67 works.

Cant go back to Windows because of valid internal reasons.'

The only difference I see between Windows DHCP service and Cisco DHCP serviced packets is that during the Windows DHCP offer I see Option 60 being sent by Router to Client, same is not done during Cisco DHCP Offer

Below are the scenarios that worked separately for device type, but I am looking for configuration that works for both/all of the device types.

Device	IP Helper	VLAN	Option 60	Option 66	Option 67	Opt 67 filename	success
Microsoft Surface	yes	2004	yes with PXEClient	no	no	no	YES
HP Z840	yes	2004	no	no	yes	smsboot\x64\wdsnbp.com	YES

Thank you in advance.

[Deepak Kumar]

Hi,

Try your DHCP pool configuration like this:

ip dhcp pool DATA_LAN
network 10.250.1.0 255.255.255.0
default-router 10.250.1.1
option 66 ip 10.250.1.2
option 67 ascii smsboot\x64\wdsnbp.com
dns-server 10.111.18.241 10.111.18.242
domain-name xx.local

Also noticed this bug (If option 67 is getting change): https://bst.cloudapps.cisco.com/bugsearch/bug/CSCsi10974/?rfs=iqvred

Regards,

Deepak Kumar

[prabhu050446]

Thank you Deepak for the reply.

I dont think I am impacted with that bug.

Thank you

Dharmendra

[Deepak Kumar]

Hi,
I am not saying the switch is infected with this bug. But it is shared for your information only.

Regards,
Deepak Kumar

[paul driver]

Hello

ip dhcp pool xxx
option 66 ip x.x.x.x
option 67 ascli "file path"

[prabhu050446]

Thanks a lot for the reply Paul. I tried all the combinations with Options 60, 66 and 67. If I h ave two options configured (like you suggested) then X840 works but not Surface.Below are the combinations that I already tried.

Device	IP Helper	VLAN	Option 60	Option 66	Option 67	Opt 67 filename	success
Z840	yes	200	yes	yes	no	NA	NO
Z840	yes	200	no	yes	no	NA	NO
Z840	yes	200	no	yes	yes	smsboot\x64\wdsmgfw.efi smsboot\x64\wdsnbp.com smsboot\x86\wdsmgfw.efi smsboot\x86\wdsnbp.com	NO
Z840	yes	200	no	no	no	NA	NO
Z840	yes	200	no	no	yes	smsboot\x64\wdsmgfw.efi smsboot\x64\wdsnbp.com smsboot\x86\wdsmgfw.efi smsboot\x86\wdsnbp.com	NO
Z840	yes	200	no	no	yes	smsboot\x64\pxeboot.com	NO
Z840	yes	200	yes	yes	no	NA	NO
Surface	yes	200	no	no	yes	smsboot\x64\pxeboot.com	NO
Surface	yes	200	no	no	yes	smsboot\x64\wdsmgfw.efi smsboot\x64\wdsnbp.com smsboot\x86\wdsmgfw.efi smsboot\x86\wdsnbp.com	NO
Surface	yes	200	yes with PXEClient	no	no	no	YES
Z840	yes	200	no	no	no	NA	NO
Surface	yes	200	no	no	no	NA	NO
Z840	yes	200	no	no	yes	smsboot\x64\wdsnbp.com	YES

as said earlier, the only difference I see between Windows DHCP service and Cisco DHCP serviced packets is that during the Windows DHCP offer I see Option 60 being sent by Router to Client, same is not done during Cisco DHCP Offer.

Thanks a lot.

[prabhu050446]

some of the scenarios that I tried (your suggestion using opt 66 and 67) are not listed in the table as they did not work.