So PXE booting is failing for some reason. We have three separate networks, and it works on one network, but not for another. We're using SCCM. Our firewall is fine. Open or diabled TFTP is refused but the port is open and the service is running. We've rebooted the server and tried to TFTP directly but no dice. DHCP gets the option properly. In SCCM the settings are copied exactly from the working network.
The error on the machines when trying to PXE boot right now is No boot filename received