From mboxrd@z Thu Jan 1 00:00:00 1970 From: Grant Taylor Subject: Re: Transfer ipv6 packages over ipv4 iptables gateway to ipv4 ISP's network Date: Fri, 17 Oct 2008 12:45:51 -0500 Message-ID: <48F8CF4F.3010704@riverviewtech.net> References: <1814bfe70810151332r61aa900see2931df5dddcdb0@mail.gmail.com> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: Sender: netfilter-owner@vger.kernel.org List-ID: Content-Type: text/plain; charset="us-ascii"; format="flowed" To: Mail List - Netfilter On 10/16/08 02:16, Petr Pisar wrote: > `Translating' is not proper word unless you mean real NAT-PT (Network > address translation and protocol translation). I was going to use the term "gatewaying" to describe what needed to be done between the IPv6 and the IPv4 protocols. "Translating" is usually done /with in/ a single protocol and "gatewaying" is usually done /between/ two protocols. At least that's my take on it. > If you want just to connect your IPv6 island via IPv4 Internet to > native IPv6 Internet backbone (i.e. bypass your lazy ISP), use 6to4 > (in case you have public IPv4 address on your gateway) or AYIYA (in > other case). This is called tunneling and former post enlightened it > already. *nod* > If you want to be able to connect from your IPv6 host to IPv4 only > servers in IPv4 Internet, you have to choices: > > Provide to all IPv6 hosts IPv4 connectivity (i.e. dual stack > solution), or do NAT-PT on your gateway. I think the OP is wanting to avoid dual stack despite this probably being the simpler of the options. > NAT-PT translates one protocol family into other one. However due to > some differences between these two protocols, the translation is not > seamless (like IPv4 NAPT). Thus there exist few limitations and > different solutions how to achieve it. > > I know only about RFC3142 (An IPv6-to-IPv4 Transport Relay > Translator) implementation and it's pTRTd > and totd > (http://www.vermicelli.pasta.cs.uit.no/software/totd.html). It works > following: > > IPv6 only client asks totd name server for AAAA record of IPv4 only > host. The name server provides fake answer resolving to network > prefix routed to pTRTd server. Then your client sends IPv6 TCP or UDP > packet to given fake IPv6 address, the packet recieves pTRTd server > (a userspace daemon capturing packets on TUN network interface), > pTRTd established mapping between IPv6 and IPv4 transport addresses, > translates the packet into IPv4 protocol and transmits it to the real > IPv4 only host in IPv4 Internet. Of course the pTRTd processes > returing responses and forward them to your IPv6 client as IPv6 > packets. > > Thus your IPv6 only hosts can see whole IPv4 world as a subnet in > IPv6 address space. Very interesting! I now have a reason to mess with IPv6. Grant. . . . P.S. Very good reply. I was going to try to sum up the bit about translation verses gatewaying, but I think you did a better job than I could have.