North American Network Operators Group Date Prev | Date Next | Date Index | Thread Index | Author Index | Historical Re: Fwd: 41/8 announcement
On Fri, May 26, 2006 at 07:44:04AM -0700, william(at)elan.net wrote: > > > On Fri, 26 May 2006, Bill Woodcock wrote: > > > On Fri, 26 May 2006, Mikisa Richard wrote: > > > Can't be sure what they did, but I received an e-mail asking me to > > check > > > on my connectivity to them and well, it worked. > > > >Presumably they're double-natting. I had to do that once for Y2K > >compliance for three large governmental networks that were all statically > >addressed in net-10 and wouldn't/couldn't renumber in time. In fact, > >there were _specific hosts_ which had the same IP address, and _had to > >talk to each other_. Gross. But it can be done. > > Please explain how. I simply can't imagine my computer communicating > with another one with exactly same ip address - the packet would never > leave it. The only way I see to achieve this is to have dns resolver > on the fly convert remote addresses from same network into some other > network and then NAT from those other addresses. Here's how with dual proxies. Presumably dual NATs use multiple IPs from different parts of the intermediary network. proxy1----------------+ +-----------------proxy2 |.1 |.1 |.2 |.1 ======= 10.0.0.0/24 ======= x.y.z.0/24 ======= 10.0.0.0/24 |.15 |.15 host server If you are using a good mail reader, the above ASCII art will come through unscathed. If it does not come through unscathed, you are not using a good mail reader. ;-) net1: 10.0.0.0/24 host = 10.0.0.15 proxy1 = 10.0.0.1 net2: x.y.z.0/24 (NOT 10.0.0.0) proxy1 = x.y.z.1 proxy2 = x.y.z.2 net3: 10.0.0.0/24 [it used to belong to the guy down the block but i bought it at a garage sale and had to merge the two networks] proxy2 = 10.0.0.1 server = 10.0.0.15 Host has proxy set to 10.0.0.1. Rather than resolving "server", it sends a Web query for "http://server" to 10.0.0.1. Proxy1 gets it. It has been told that "server" is on the other side of proxy2. Rather than resolving "server", it forwards the Web query for "http://server" to proxy2, at x.y.z.2. Proxy2 breaks this query down, resolves "server" using _local_ DNS to 10.0.0.15. Sends the query to server, receives the response. Passes the response back to proxy1, which passes it back to host. Capisci? -- Joe Yao ----------------------------------------------------------------------- This message is not an official statement of OSIS Center policies.
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