[Asrg] For DNSBLs, embedded IPv4 in IPv6

[Chris Lewis]

Jose-Marcio Martins da Cruz wrote:

> 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.

Right: MOST DNSBLs return A records to bitmap/flag listings.

However, there are a few DNSBLs that return machine-readable in the TXT. 
  Eg: routeviews.