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Re: Whoa; the 3 network?
A bit behind on mail owing to the pressure of not shopping early enough but (while I'm waiting for the turkey to cook), having read through the whole thread to date, I couldn't resist a comment on the statement below... At 10:13 PM 12/23/97 -0500, you allegedly wrote: >Right, but since each border router off of the public Internet can't >advertise anything smaller than /24 (would *your* router accept an >advertisement for 184.108.40.206/27?), each seperate office needs at least a /24. >Yeah, NAT can take care of the internal addressing, but you're still stuck >with the fact that you "only" can have 256 seperate border routers. [snip for brevity] Just where are the "border routers" connecting to? Thanks to smd and others (in reaction to the table growth and flap frequency) a couple of years ago many places on/in the net will not advertise/accept anything less than a Classful C /19 (in certain ranges, granted) and will not accept anything longer than a /16 or /8 from "classful" B or A networks. This eventually matched the RIPE rules for address allocation - nothing longer than a /19 from RIPE. Sprint published their rules (here on NANOG and elsewhere) and others worked on roughly the same set. The rules haven't changed much!! Ergo - if your prefix is long you won't be routed! e.g. 220.127.116.11 /8 (or even a bit longer maybe) should be reachable but 18.104.22.168 /25 will probably not! However 22.214.171.124 should be reachable internally via wherever 126.96.36.199 /8 is advertised. If you have a small site connected only via the public net (i.e. to an ISP) you need to get a routeable address space from YOUR UPSTREAM PROVIDER from their address block!! (note:- if you _are_ the provider you will obviously be aggregating to avoid the flaps/entries issue so this doesn't affect you - you reach your internal hosts via your IGP tables!!). If you want the flexibility to change providers when they scr*w up [they will :-) ] then you need a private address space behind a NAT-type device and then get a /32 from "NE1-the-ISP.com". Renumbering a single host is NOT A PROBLEM! How GE deal with things is their headache for now, but with the filtering rules above and the renumbering necessary to get small sites routed in public it strikes me that it would be more sense for them to renumber ONCE into the 10.0.0.0 space and use NAT or something similar to fake-out the IPV4 routing. It doesn't take a rocket-scientist to work out that unused IPV4 space (i.e. space not populating public routing tables) will at some future time become reclaimed either by default or, as elsewhere suggested, by being traded as a commodity. Of course, IPV6 becomes the lazy way out - "there'll be plenty of addresses for everybody" (deja vu?) - if/when it arrives! Something to ponder over dinner..... Have a good (insert relevant reason for celebration here) holiday. -H-