hii

I'am trying to install custom linux on my HP machine over network
I have a HP machine which has three network cards ,1 onborad 2 external.
Bios shows pxe boot has only the option for selecting the onboard network card however when the linux boots over network it requests ip information for external network card(eth0) .

I have also made a dhcp entry for external card however for some reason it is not able to get the ip address. i checked with the DHCP server logs its properly issuing the Ip address for the external network card.

Could this be a driver issue with external network card,Any idea about how to resolve this ?