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boot ipxe with 2 LAN
2020-08-24, 17:50
Post: #1
boot ipxe with 2 LAN
Hi all,
I have 2 lan in my local network which communicate well with each other.
There is a dhcp server in each lan.
LAN1 = and LAN2 = / 24.
But my servers can't boot in ipxe, they can't access the dhcp server on LAN1. How to do ?
Thank you !
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2020-08-25, 08:45 (This post was last modified: 2020-08-25 09:02 by MultimediaMan.)
Post: #2
RE: boot ipxe with 2 LAN
Which interface tries to boot first?
LAN1 = or / 24?

A few things to note:

a: If you are using ipxe.kpxe or ipxe.kkpxe understand that iPXE will only "see" the interface which it booted from. UNDI is limited to One interface.

b: To have iPXE load native drivers (generally too large for UNDI ipxe.kpxe or ipxe.kkpxe) you will need to chain a *.pxe binary to load all interfaces (Assuming native driver support exists for all of the NICs in the system).

Sample code to chainload a native driver binary from an ipxe.kpxe or ipxe.kkpxe binary using the Root Path (DHCP Option 17) variable: (~350kB):
chain ${17}/ipxe.pxe

c: If you are using an iPXE EFI Binary (SNP/NII or Native drivers) you may need to customize your boot script to use the correct interface(s) in the manner you want them used.

d: Pay particular attention to the Route command/ Default Gateway... if you use DHCP on multiple Interfaces remember that iPXE may be confused as to the correct Gateway to use (configure the interface you want to utilize for the control plane, last).

Personal/Professional Note: I have had to work through these issues on some very complex production installations (48+ Interfaces), I generally used as few interfaces as needed to get the job done. The most interfaces used actively was two (2) during the PXE boot/ bootscript process, but the facility for using four (4) Interfaces was built into the boot script (Typically, the running OS would use ~10 bonded interfaces when in the OS, but for the PXE boot only two interfaces were used - with failure escapes to emulate a Bond {Mode 1} on the Interfaces during boot in case there was a Cable/Interface or Switch failure)... the DHCP Source network (Routable Public interface) and the NFS (Private Boot Storage Interface) needed for the NFS Roots OS to boot. The DHCP server may need some customization to handle some of those scenarios (DHCP/ Network Engineers may openly question your sanity/ knowledge); It takes time to write good scripts to correctly handle various failure modes/ escapes, so be patient as you work through this.


"Thus far, you have been adrift within the sheltered harbor of my patience..."
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