On Tue, 20 Apr 2010, Edward Ned Harvey wrote: Hi Edward.
> No, NAT will not be necessary or useful anymore in IPv6 for the sake of > creating address space. Yes, NAT could be useful to mask your internal > network topology from the wild world web. If you do implement NAT to mask Does it though? To me "network topology" refers to how the subnets relate to one another - not the actual IP addresses used. If someone can see an internal address on my network they can't tell where in my network it is. Various sorts of probing can be used to derive the topology to an accessible IP address but methods to limit or prevent these probes are well understood. I'll tell you what does expose internal network topologies - SMTP headers and that happens right now whether NAT is in use or not. Any other application which records its path through the network in the application headers is similarly exposing network topology. For the record this is my take on NAT in IPv6. I've presented this argument a number of times in recent years. An entire generation of sysadmins have grown up thinking of NAT as an integral part of networking. As a result some sites will use many:one NAT or one:one NAT and some won't. Eventually it will become evidence that NAT offers no appreciable benefits but costs real money to maintain. Usage will fade away over a number of years. I expect CFOs and sysadmins will be in agreement that it has to go. > (4) There's no reason IPv4 needs to die. In all likelihood, devices which I predict IPv4 will only exist in isolated pockets by about 2020. The reason is the same one as above. Maintaining dual stack systems requires additional resources (money). Apps will need to support it, testing/QA will need to occur, etc. Companies will monitor the proporation of users accessing their systems over IPv4 or IPv6. As long as dual stack client machines try IPv6 first the proportion of IPv4 will steadily reduce. Eventually it will hit a point when it is no longer cost effective for companies to support IPv4. While we may argue about whether my predicted timeframe is accurate I think the general trend must hold true. Cheers, Rob -- Email: rob...@timetraveller.org IRC: Solver Web: http://www.practicalsysadmin.com Open Source: The revolution that silently changed the world _______________________________________________ Discuss mailing list Discuss@lopsa.org http://lopsa.org/cgi-bin/mailman/listinfo/discuss This list provided by the League of Professional System Administrators http://lopsa.org/
