The Internet Protocol Journal - Volume 8, Number 3

Protocol transitions are never easy, particularly not when they involve something so fundamental as the Internet Protocol (IP). Organizations considering a move to IPv6 must consider many factors when deciding on the timing for such a deployment. One of the first questions that arises is: “When will the IPv4 address space actually run out, forcing us to use IPv6 instead?” That question is not a new one; it was being asked in the early 1990s when the IPv6 effort was started. Several factors, such as the deployment of Classless Interdomain Routing (CIDR) and Network Address Translation (NAT), have “delayed the inevitable,” and perhaps led to some complacency on the part of network operators. In this issue we examine the topic of IPv4 address space depletion in more detail. Our main article is by Tony Hain, and it is followed by a response from Geoff Huston and a roundtable discussion with Tony, Geoff, Fred Baker, and John Klensin. We would also like to hear from our readers on this important topic. Please send your comments to ipj@cisco.com.

As an old-time network and UNIX user, I am a big fan of tools that allow simple terminal access to remote host computers. My “Internet career” started in Norway in 1976, where I used Telnet to access machines in California through the ARPANET. Today, I still access remote servers through a simple terminal interface, but Telnet has been replaced by the Secure Shell (SSH) Protocol for all the obvious security reasons. SSH is used not just for terminal traffic—it also can be configured to provide secure tunnels to a variety of services such as Webpages and file transfers. Ronnie Angello explains the details in our second article.

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