[Cerowrt-devel] Wicked OT: 240.0.0.0/4 netblock

[Jonathan Morton]

> On 19 Oct, 2018, at 9:36 pm, Rich Brown <richb.hanover at gmail.com> wrote:
> 
> MY QUESTION: I have always believed that this netblock is not routable. Is this true? (A simple yes/no answer would be sufficient.)

According to https://www.iana.org/assignments/iana-ipv4-special-registry/iana-ipv4-special-registry.xhtml the 240/4 netblock is:

NOT valid as a source or destination address for packets between devices.

NOT forwardable.

NOT globally reachable.

IS "reserved by protocol":

o  Reserved-by-Protocol - A boolean value indicating whether the
      special-purpose address block is reserved by IP, itself.  This
      value is "TRUE" if the RFC that created the special-purpose
      address block requires all compliant IP implementations to behave
      in a special way when processing packets either to or from
      addresses contained by the address block.

I'm sure you could use those addresses in a closed, controlled laboratory network - but not in anything you plan to deploy commercially or publicly.  It would be better to use IPv6, IMHO.

 - Jonathan Morton