[Asrg] For DNSBLs, embedded IPv4 in IPv6

[Jose-Marcio Martins da Cruz]

John Levine wrote:

>> Could someone explain why a DNSBL needs to return IPV6 addresses?
> 
> I don't know anyone who thinks that a DNSBL should return anything
> other than A and TXT records.  What leads you to believe otherwise?

A and TXT records were the way found, years ago, to implement DNSBL 
without creating new kind of DNS records.

In fact, as long as I understand, the A record is useful to return a 
machine handleable code allowing to specify, why the record is listed. 
The TXT record contains human readable information.

As long as IP address is the usual result of an A query, an IPv4 address 
is the result usually returned by DNSBLs.

If something should be done about that, it's only to improve coding, not 
to add another redundant type of result.