Apr.11

PXE Wizardry

Today was our (partial) production cutover from SCCM 2007 to SCCM 1511.
The main change is that new machines we set up starting today are using the new deployment process. It’s not so much of a technical thing as a “Use the new process instead of the old one” thing.

Well, there was one technical change… and it was complicated: PXE Booting. Up until yesterday, everyone’s been using USB or ISO files to boot to the new deployment environment. But with this cutover, we can repoint PXE booting from SCCM 2007 to the shiny new stuff.

Here’s some things to be aware of as part of the process:

*Get rid of your DHCP Server and Scope options
No, really. You don’t want to set options 60, 66 or 67. Otherwise you won’t be able to support a mix of UEFI native and legacy BIOS hardware platforms.

*Do make sure you have IP Helpers configured on your network gear
Call up your network team, bribe them with beer, and tell them that you need an IP helper added to every VLAN where you deploy. They’ll need the IP address of your local SCCM distribution point.

*When it doesn’t work…
In my case I was getting a PXE error about not having a boot file. It looked like it wasn’t even getting an IP address. I ended up using Wireshark to track DHCP traffic and found that my new SCCM server wasn’t responding to PXE requests. Logs on the server made it seem like the request never even made it there. Root cause: We had a firewall blocking UDP port 67 from getting to the new SCCM server. Once we got standard ports open (UDP 67-69, 4011, 63000-64000) things started working.
https://ozmsguy.wordpress.com/2012/01/20/sccm-pxe-and-ip-helpers/ really helped me out!

*Stop deploying task sequences to the “All Unknown Computers” collection
Again, if you use a combo of UEFI and BIOS based platforms, this will give you some trouble. Separate out the deployments for 32- and 64-bit systems.
http://247sccm.com/sccm-2012-r2-pxe-with-uefi/ really helped me out!

*There’s a lot of misinformation or partial answers out there
Just be aware in your google-fu. Lots of people not fully explaining the problem and their particular conditions. The “I’m feeling lucky” button is likely to get you into trouble!

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