2. Problems

   The embedding of IP addresses in products has caused an increasing
   number of Internet hosts to rely on a single central Internet
   service.  This can result in a service outage when the aggregate
   workload overwhelms that service.  When fixed addresses are embedded

   in an ever-increasing number of client IP hosts, this practice runs
   directly counter to the design intent of hierarchically deployed
   services that would otherwise be robust solutions.

   The reliability, scalability, and performance of many Internet
   services require that the pool of users not access a service using
   its IP address directly.  Instead, they typically rely on a level of
   indirection provided by the Domain Name System, RFC 2219 [6].  When
   appropriately utilized, the DNS permits the service operator to
   reconfigure the resources for maintenance and to perform load
   balancing, without the participation of the users and without a
   requirement for configuration changes in the client hosts.  For
   instance, one common load-balancing technique employs multiple DNS
   records with the same name; the set of answers that is returned is
   rotated in a round-robin fashion in successive queries.  Upon
   receiving such a response to a query, resolvers typically will try
   the answers in order, until one succeeds, thus enabling the operator
   to distribute the user request load across a set of servers with
   discrete IP addresses that generally remain unknown to the user.

   Embedding globally-unique IP addresses taints the IP address blocks
   in which they reside, lessening the usefulness and mobility of those
   IP address blocks and increasing the cost of operation.  Unsolicited
   traffic may continue to be delivered to the embedded address well
   after the IP address or block has been reassigned and no longer hosts
   the service for which that traffic was intended.  Circa 1997, the
   authors of RFC 2101 [7] made this observation:

      Due to dynamic address allocation and increasingly frequent
      network renumbering, temporal uniqueness of IPv4 addresses is no
      longer globally guaranteed, which puts their use as identifiers
      into severe question.

   When IP addresses are embedded in the configuration of many Internet
   hosts, the IP address blocks become encumbered by their historical
   use.  This may interfere with the ability of the Internet Assigned
   Numbers Authority (IANA) and the Internet Registry (IR) hierarchy to
   usefully reallocate IP address blocks.  Likewise, to facilitate IP
   address reuse, RFC 2050 [1], encourages Internet Service Providers
   (ISPs) to treat address assignments as "loans".

   Because consumers are not necessarily experienced in the operation of
   Internet hosts, they cannot be relied upon to fix problems, if and
   when they arise.  Therefore, a significant responsibility lies with
   the manufacturer or vendor of an Internet host to avoid embedding IP
   addresses in ways that cause the aforementioned problems.