The customer was migrating from PVS BIOS based target devices to PVS UEFI based target devices.
BIOS based target devices were deprecated in PVS 2203, and all customers should be migrating to UEFI based target devices.

The customer was using VMware based target devices, and was reconfiguring target devices to EFI boot. The customer observed that when previously working target devices were reconfigured in vCenter for EFI boot, they failed to successfully PXE boot.

Requirements for UEFI PXE boot were validated:

• DHCP scope option 66 was configured as a single IP address of a PVS server
• DHCP scope option 67 was configured for pvsnbpx64.efi
• DHCP scope option 11 was configured with all PVS servers streaming IPs

Network traces were captured on the PVS server and on the target device network when attempting to PXE boot a UEFI based PVS target device. These traces showed that some of the TFTP packets sent from the PVS server were not getting delivered to the target device. 

Doing the same traces with BIOS based targets showed all TFTP packets sent from the PVS server being delivered to the PVS target.

The network traces showed a different source port range was used by UEFI PXE clients compared with BIOS PXE clients.

The customer engaged their network team to review blocked packets between the PVS servers and PVS targets when PXE booting, and allow additional ports. 

Problem Cause

Depending on the hypervisor used in the environment, UEFI based PXE VMs may use a different ephemeral port range for PXE boot related TFTP transfers when compared with BIOS based PXE booting VMs. The customers network team reviewed the network traces and unblocked the required network ports.