Katie,
[ipv4_address] is an IPv4 address of the name server
[ipv6_address] is an IPv6 address of the name server
It would be helpful to include details about the accepted syntax for these addresses. For instance: [ipv4_address] is an IPv4 address of the name server in dotted quad form [ipv6_address] is an IPv6 address of the name server in the preferred textual canonical form (Sect 2.2.1, RFC 4291) The IPv6 textual compressed form (Section 2.2.2, RFC 4291) is/is not accepted (cross as necessary). The IPv4/IPv6 textual mixed form (Section 2.2.3, RFC 4291) is/is not accepted (cross as necessary).
nserver: ns1.example.com 168.0.0.1
It would be better to use RFC 3330 documentation IP addresses, e.g. nserver: ns1.example.com 192.0.2.0 Best regards, Marcos P.S. Btw, if non-preferred IPv6 textual forms are accepted, will the output of e.g. whois deliver the original or the preferred form?