I'm wondering if there is any good documentation or other advice that can help us optimize our PXE booting. In the past we've always used DHCP scope options 60, 66, 67, and 43 to point our clients to the PXE server. If the PXE representative is also the DHCP server then only option 60 is needed, but if we want PXE to point to a PXE rep that is not the DHCP server we have used options 66, 67, and 43 to point it to the correct server and boot file. This solution works great if we just stick to 32 bit PXE booting, but doesn't allow any flexibility if we want to use both 64 and 32 bit booting.
I am aware that we can accomplish our goal by using the self-elected subnet service on clients in the same subnet, but this has proven unreliable for us. We much prefer to use servers as our PXE representatives, which reside on a different subnet than the clients. Are there any best practices out there to make PXE booting across subnets happen without the use of DHCP scope options? We've tried putting the IP address of the PXE rep in the IP helper table, but it doesn't help. We are running version 2017.3.