> The ultimate solution to IPv4 exhaustion is, of course, the complete transition of the Internet to IPv6, however, this will take time and until then there will be (by definition) networks and sites which only support IPv4. This requires other networks and sites, even if they support IPv6, to maintain IPv4 connectivity, which in turn requires some number of IPv4 addresses. For that reason, IPv4 exhaustion certainly is an issue to be understood and dealt with, especially by those who are building new networks and services.

That's what I heard in college in 1999.