nanog mailing list archives
Re: Fwd: 41/8 announcement
From: "Stephen Sprunk" <stephen () sprunk org>
Date: Fri, 26 May 2006 15:11:37 -0500
Thus spake "william(at)elan.net" <william () elan net>
On Fri, 26 May 2006, Bill Woodcock wrote: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.
Unfortunately, I've done this several times, most notably within one company that had multiple instances of 10/8 that needed to talk to each other. A decent (if one can use that term) NAT device will translate the addresses in DNS responses, so two hosts that both live at 10.1.2.3 will see the other's address as, for example, 192.168.1.2, both in DNS and in the IP headers.
It's extremely ugly, but that's what one gets for using private address space. This exact scenario was a large part of why I supported ULAs for IPv6.
S Stephen Sprunk "Stupid people surround themselves with smart CCIE #3723 people. Smart people surround themselves withK5SSS smart people who disagree with them." --Aaron Sorkin
Current thread:
- Re: 41/8 announcement, (continued)
- Re: 41/8 announcement Suresh Ramasubramanian (May 24)
- Message not available
- Fwd: 41/8 announcement Richard Mikisa (May 24)
- Re: Fwd: 41/8 announcement bmanning (May 24)
- Re: Fwd: 41/8 announcement Richard Mikisa (May 24)
- Re: Fwd: 41/8 announcement william(at)elan.net (May 25)
- Re: Fwd: 41/8 announcement Mikisa Richard (May 25)
- Re: Fwd: 41/8 announcement Bill Woodcock (May 26)
- Re: Fwd: 41/8 announcement william(at)elan.net (May 26)
- Re: Fwd: 41/8 announcement Bill Woodcock (May 26)
- Re: Fwd: 41/8 announcement Joseph S D Yao (May 26)
- Re: Fwd: 41/8 announcement Stephen Sprunk (May 26)
- Re: Fwd: 41/8 announcement Peter Corlett (May 30)
- Re: Fwd: 41/8 announcement Valdis . Kletnieks (May 30)
- Re: Fwd: 41/8 announcement steve (May 26)
- Re: 41/8 announcement Patrick W. Gilmore (May 24)
- Re: Fwd: 41/8 announcement Jon Lewis (May 27)