TV> The RFC require circular consistence i.e. the reverse query
TV> of an IP you got from an A record should point to the name
TV> you started with.
No, they do not. The address->name mapping in DNS is not required by the RFCs
to be the exact inverse of the name->address mapping. Nor is there a good
reason for having such a requirement.
It is not even true that the (misnamed) "security measures", that are employed
by some providers of various TCP services, require this. These measures
require that an address->name->address mapping include the original address in
the final result set, not that a name->address->name mapping be an identity.