If you are looking to change Citrix Provisioning Services from PXE to TFTP, consider DHCP server options 60 and TFTP server port 69 to be opened.
option 60: pxe client
option 66: FQDN or IP Address of TFTP server
option 67: ARDBP32.BIN.(specifies which file needs to be downloaded from TFTP server)
Configure a Microsoft DHCP server in order to get Citrix PVS PXE boot working:
port 69 for communications over TFTP, if port 69 is blocked this will prevent the download of the .bin file needed for the boot process.
netstat -an -p udp | find “:69”
With Citrix PXE built-in service the client during the startup, send broadcast requesting the option 60 (PXEClient) and all PVS Server that handle this service will answer this request and send the file called bootptab. The file bootptab make reference of ardbp32.bin file that contain the image file for the target device.