HOW TO: Relay PXE clients in other subnets
  • KB ID: AA-00545
  • Created: 09/08/2011 10:54 AM
  • Updated: 05/23/2017 3:24 PM
  • Views: 5320
  • 2 Ratings


You like to PXE boot clients in other subnets than the Columbus server resides. But since PXE is based on broadcast the request is not routed to  the Columbus server




To guide clients booting-up on other networks to the correct Columbus server, there are two choices:

  1. configure DHCP Relaying or IP-Helpers on the routers
    First entry: DHCP server
    Second entry: Columbus server (Proxy DHCP)
  2. setting Option 43 on your DHCP servers - If set UEFI boot won't work anymore

For installations where routers are not configurable, Option 43 is the only choice. The hex value required in Option 43 can be a bit difficult to determine. For this we provide a calculator to create the appropriate strings.



UEFI PXE Boot does not support Option 43 anymore. If you use such clients, you will have to configure your routers.



DHCP Calculator, Subnets, IP Helper, Relay


C6, C7


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