ISC DHCP Server scope error

dhcpdhcpdisc-dhcp

Why am I getting the following error after modifying my dhcpd server config?

option space definitions may not be scoped

Best Answer

This error occurs because scope options need to be defined in the top level of the configuration and not within any code block like a group:

#This needs to be defined outside of any code block
option space MSFT;
option MSFT.nbt                 code 1 = unsigned integer 32;

Related Solutions

Accessing DHCP Client’s vendor-encapsulated-options

If you can guarantee that the client sends the same options in the same order every time, you can use substring and option vendor-encapsulated-options to parse the options manually:

if 01:01:01 = substring( option vendor-encapsulated-options, 0, 3 ) { ... }
if 02:02:ab:cd = substring( option vendor-encapsulated-options, 3, 4 ) { ... }

If those two guarantees don't hold true, however, the only remaining option is regex-based matching, but beware the possibility of an option (code-length-contents) being full contained in the contents of another option.

Isc dhcpd: how to insert option 61 (client id) into dhcpoffer

Yes, you can set options based on conditional statements in the ISC dhcpd server. Specifically you can test if the dhcp-client-identifier option is present in the incoming DHCP packet, and if it is set the option for the response packet to the incoming value by this expression:

   
# other options in scope ...
if exists dhcp-client-identifier {
  option dhcp-client-identifier = option dhcp-client-identifier;
}
# other options in scope ...

The left side of the = sets the server parameter name, the right side data expression will return the contents of the parameter name from the client packet.

For more info see man dhcp-eval and the SETTING PARAMETER VALUES USING EXPRESSIONS section at the bottom of man dhcp.conf

Best Answer

Related Solutions

Accessing DHCP Client’s vendor-encapsulated-options

Isc dhcpd: how to insert option 61 (client id) into dhcpoffer

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