where is class E ip addresses?

Question

I am reading Richard Stevens' TCP/IP illustrated Vol1.He said class E ip addresses are reserved for future use.Considering he wrote the book at 1994,now is the future.So where is the class E ip addresses?

I tried to ping 240.0.0.3 but windows returns

Destination specified is invalid

thanks.

Answer 1

IP Address Class E and Limited Broadcast The IPv4 networking standard defines Class E addresses as reserved, meaning that they should not be used on IP networks. Some research organizations use Class E addresses for experimental purposes. However, nodes that try to use these addresses on the Internet will be unable to communicate properly.

Answer 2

Class E networks are used for R&D and were never documented or utilized in a standard way.

Answer 3

Yep, the book is from 1994. Try reading something about Classless Inter-domain Routing (CIDR). Classes in that form do not exist anymore. (And 240.x.x.x seems like a multi-cast address.)

Answer 4

There was some discussion a couple of years ago about making Class E addresses available for general use. However, it was discovered that lots and lots of software recognizes Class E addresses and reports errors. The effort to fix all that software would take too long since we will run out of IPv4 addresses by the end of 2011, and the deployment of IPv6 is now in full swing.

So, essentially the IETF decided to abandon Class E addresses.