1 voteJerry Abbott commented
I am currently on ConfigMgr 1810 with all of the 1810 Hotfix rollups applied.
I meant to come back and update this. While setting the AllowedMPs registry key does generate what appears to be desired activity in the SMSPXE log, as shown in the screen snip, I've found that I still had issues where my PXE clients would still get directed to the wrong MP, even though the PXE-Enabled DP also has an HTTPS MP hosted on it as well.
I still use the AllowedMPs registry key, but I also found that I have had to use a CI to maintain the "ManagementPoints" value in the HKLM\SOFTWARE\Microsoft\SMS\DP key.
I encountered this problem, as I needed to introduce an HTTP Management Point into my infrastructure to handle some client communications for some Stand-Alone Media builds. When I introduced the HTTP MP into the environment, even though I un-select it from being published with the other MPs in the Management Point Component Properties, and it is not a member of any Boundary Groups for clients, it still gets offered to PXE Clients and gets placed in the PXE-Enabled DP's ManagementPoints list.