UDHCPC modifications?

  • Have there been any changes in the FOS kernel that would affect how UDHCPC operates, or how long it waits for a DHCP lease?

    We’re on kernel 4.7.1

  • Sorry to pop this bubble… Due to communication issues, I thought PortFast was turned off for this case. I’ve found out that PortFast was in fact turned on.

  • It seems that this change would only affect certain switches with certain configurations - with portfast being off. I think older switches would perhaps work but newer ones won’t, too fast of a CPU in them. That’s what I’m seeing right now.

  • I feel like a middle man.

    Tom says - the kernel loads the NIC as part of the kernel loadup now.

    The difference - the time the nic is down is way, way shorter. So short, the switches apparently don’t even notice. So you can get away with portfast being off.

  • Just spoke with @Tom-Elliott

    He now takes the IP that iPXE gets from DHCP, and passes it as a kernel argument - and the latest FOG kernel 4.7.1 accepts this IP and uses it. So if the IP is already configured in the kernel, UDHCPC doesn’t need to get a new IP - but it still gets DNS addresses. If for whatever reason the kernel doesn’t get passed an IP, UDHCPC will request one. It operates as a sort of failsafe now.

    This also means the latest kernel should work with 1.2.0 in theory - no promises.

    Also - This change allows FOG to work with PortFast turned OFF. Yes, you heard me right. Tested working at work.

    @Developers @Moderators @Developers

  • Senior Developer


    The 4.7.1 kernels actually have IP loading back as a default part of the kernel load up (meaning 4.7.1 and up should work again for 1.2.0 and earlier too).

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