$TTL 120

@               IN      SOA     ns1     hostmaster (2018041509
                                                    300
                                                    150
                                                    600
                                                    60)

                IN      NS      ns1
                IN      NS      ns2


ns1             IN      A       192.168.0.159
ns2             IN      A       192.168.0.160

blah            IN      A       192.168.0.141

Child Centric non sticky:
PPPCCCPPPCCCPPPCCCPP

Child Centric sticky
PPPCCCCCCCCCCCCCCCCC

Parent Centric
PPPPPPPPPPPPPPPPPPPP

Unauthenticated RRs received and cached from the least trustworthy of
those groupings, that is data from the additional data section, and
data from the authority section of a non-authoritative answer, should
not be cached in such a way that they would ever be returned as
answers to a received query.  They may be returned as additional
information where appropriate.  Ignoring this would allow the
trustworthiness of relatively untrustworthy data to be increased
without cause or excuse.

[...] Note that throughout this document, "authoritative" means a
reply with the AA bit set.