Updated gpxe packages that fix one bug are now available for Red Hat Enterprise Linux 6.
The gpxe packages provide an open source Preboot Execution Environment (PXE) implementation and bootloader. gPXE also supports additional protocols such as DNS, HTTP, iSCSI and ATA over Ethernet.
Previously, the virtIO gPXE driver padded all packets to maximum length. This could confuse some gateways because the Ethernet standard is to pad only packets of up to 64 bytes in length. Due to this issue, virtual machines with a virtIO NIC (network interface card) failed to connect to the PXE server behind a gateway. Subsequently, the PXE boot failed. This update pads only packets of up to 64 bytes in length. Now, virtual machines with a virtIO NIC connect to the same PXE server without further problems.
All gPXE users are advised to upgrade to these updated packages which fix this bug.