Error: "PXE-E55" when using DHCP option 43 on a Linux DHCP server

Products

• Deployment Solution

Issue/Introduction

Setting up option 43 on a Linux DHCP server using the hexadecimal string generated by Forced mode utility will not work, and the following error is returned:

PXE-E55

Forced mode utility will generate a hexadecimal string using the following format (Which is ok for Windows DHCP servers):

option vendor-encapsulated-options   -  24AC1141131273756e646863702d

If you use this format when setting up option 43 on a Linux DHCP server, it will not work.   The value of this option has to be set up using a text string colon-separated list of hexadecimal values.  For example:

option vendor-encapsulated-options      -    12:73:75:6e:64:68:63:70:2d:73:65:72:76:65:72:31:37:2d:31

Environment

DS 8.x

Cause

The cause of this issue is when using a Linux Based DCHP server you need to be careful as the format varies from Windows Based DHCP server.

Resolution

The value for option 43 on a Unix/Linux DHCP server has to be set using a text string colon-separated list of hexadecimal values.  For example:  

option vendor-encapsulated-options      -    12:73:75:6e:64:68:63:70:2d:73:65:72:76:65:72:31:37:2d:31

Option 43 value can be generated using the PXE Forced Mode Utility, forced mode utility has to be run on the PXE server, as it is going to generate an hexadecimal value with the "vendor specific information", once you have generated the hexadecimal value, modify it adding colons as in the example above.