This bug was initially created as a copy of Bug #2196452 I am copying this bug because: During the work on the original bug, it was determined that 16.2 has an undocumented parity gap for OVN implementation for reverse DNS support for internal DNS records. ML2/OVS supports it in Train (16.2). The support is available in OVN 2021 included with the release, but the neutron piece is not backported to the branch. I've asked the original bug reporter to report a separate bz to request this new feature, but in the meantime, (or in case we don't backport the feature to the branch), we should document this limitation in documentation. FYI I've looked at the following page to confirm that this limitation is not documented yet: https://gitlab.cee.redhat.com/rhci-documentation/docs-Red_Hat_Enterprise_Linux_OpenStack_Platform/-/blob/osp162-train/common/networking/ref_ml2-ovn-limits.adoc?ref_type=heads
Note that this is specific to 16.2. 17.x has support for the feature in neutron.