Hi Marc, flex-option actions are performed last just before packet sending: "These actions are carried out during the final stages of constructing a query response packet, just before it is sent to the client." https://kea.readthedocs.io/en/kea-2.4.0/arm/hooks.html#libdhcp-flex-option-so-flexible-option-actions-for-option-value-settings It is meant to allow arbitrary manipulation of options and values sent TO the client in a response.
So, DDNS updates have either already been sent or, at least, the values to be used have, most likely, already been obtained. In any case, the values wouldn't be re-parsed. Option 15 is meant to convey search domains TO the client and so should not have any content FROM the client: https://www.rfc-editor.org/rfc/rfc2132.html#section-3.17 and so would not be suitable for use in DDNS. Option 81 seems to contain the FQDN that will be used by Kea to update DDNS. Is the problem here that the client is not attaching option 81? There are various parameters that can be used to control ddns behavior: https://kea.readthedocs.io/en/kea-2.4.0/arm/dhcp4-srv.html#ddns-for-dhcpv4 perhaps you can synthesize some values to use for clients that do not send option 81? Thank you, Darren Ankney On Fri, Sep 8, 2023 at 5:27 PM Marc Richman <marc.rich...@berkshiregrey.com> wrote: > > I got somewhere but not where I wanted to be.... > > I managed to get option 81 to the correct value using the flex_option hook it > is a bit ugly but wireshark confirms the values are correct > > > BUT it is still handing off the original value to DDNS! Does anybody have > ideas as to why that would happen? (or how to fix it) > > > (FWIW: I tried using option[15] instead of the string but it wasnt defined?!? > even though it was being sent in the packet) > > > {"library": "/usr/lib/x86_64-linux-gnu/kea/hooks/libdhcp_flex_option.so", > > "parameters": { > "options" : [ > { "code" : 81, > "supersede" : "0x03 + 0x00 + 0x00 + option[12].hex + > '.bos.berkshiregrey.com'" > } ] } } > > > > -- > ISC funds the development of this software with paid support subscriptions. > Contact us at https://www.isc.org/contact/ for more information. > > To unsubscribe visit https://lists.isc.org/mailman/listinfo/kea-users. > > Kea-users mailing list > Kea-users@lists.isc.org > https://lists.isc.org/mailman/listinfo/kea-users -- ISC funds the development of this software with paid support subscriptions. Contact us at https://www.isc.org/contact/ for more information. To unsubscribe visit https://lists.isc.org/mailman/listinfo/kea-users. Kea-users mailing list Kea-users@lists.isc.org https://lists.isc.org/mailman/listinfo/kea-users
