DHCP option names are not standardized and option names that works with dnsmasq doesn't work with Contrail. By trying to switch to dhcp option values we found that it breaks dnsmasq case. As dnsmasq always set `siaddr` field in dhcp reply to dnsmasq host ip unless `server-ip-address` is not configured. This field is treated by pxe client as tftp server more information about this may be found here https://tools.ietf.org/html/rfc5859.
We left this dnsmasq internal option `server-ip-address`. All dhcp providers we tried contrail/dnsmasq/isc just silently ignore unknown options. But still we concern that it may blow up with others. This is not an actual bug, it is only our concern. And we wondered that it maybe standardized on Neutron side somehow or at least basic validation is provided.
If someone has the time to work on this, seems like maybe it could come through the blueprint/spec process, just to make sure everyone is on the same page.
[1] https:/