Hmm, there is some interesting idea in this message - to keep some track of the initial (pre-NAT) address/port somewhere in the packet (may be in the start packets, at least)...

I think this has merit. If I understand RSIP correctly (which is meant to replace NAT), you need an RSIP enabled client and an RSIP enabled router. Therefore, people are considering doing deployment changes. Problem is that once the pkt leaves the RSIP enabled router destined to the Internet, one has no idea that the IP address and port number (auto-generated by the RSIP router) are really masking a NAT address. By tweaking a bit in the IPv4 header (that is transitive and won't harm anyone by looking at it) as you suggested might make more sense and thereby give downstream users an idea that the pkt they are seeing is really an RSIP modified packet.

Basically - a merge of RSIP and your idea. Any IETF RSIP people want to pick up on this?

-Hank

...

There are a couple of unused bits in the IPv4 header that one could use.

I thought of this during the last "paper" to expand address space that circulated this summer on nanog.

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Unfortunately, the real problem is deployment. Once you decide to change

the protocol in any way that is not completely downward compatible, everyone has to deploy the modification. I'm going to hazard a guess that IPv6 will really be widely deployed by tunneling it in IPv4. And I'll hazard that much of the IPv6 traffic will just contain tunnelled "private" IPv4 traffic. Tunnel inside tunnel. So much for header compression.

...

--Dean

Around 01:13 PM 10/18/1999 -0400, rumor has it that

...

...

just a thought...

why not expand the IPv4 address field using the 'Fragment offset' and 'Identification' fields? Use those fields to mark packets at the edge with the destination AS

number, for

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example. Customer equipment could use private address space and not bother with

...

...

remarking process. (I know that the fragmentation function would be lost due to this 'extension'.) (I am also aware of transitioning problems related to what I am

jeanlou.dupont@na.marconicomms.com said: the edge proposing; the

...

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routers in the network cannot be upgrade all at once...)

thoughts/comments?

jld.

"Alex P. Rudnev" <alex@virgin.relcom.eu.net> on 10/18/99 12:46:50 PM

To: nanog@merit.edu cc: (bcc: Jeanlou Dupont/RMQ/RELTECCORP)

Subject: ISP and NAT (question and some thoughts)

Today we see the classical schema ISP/customer; this means - the customer have his own address space, requested by him (directly or undirectly) - due to the lack of public addresses, the customers are forced to use NAT; just NAT provide some extra security - ISP do not provide NAT themself; NAT configuration is not easy task and cause a lot of headache for the customers (just as a lot of money they pay to the network admins).

First question - is this picture right or it is wrong?

The second question. What prevent the _future ISP_ from some another schema, when: - the customer always use the private address space, for example, 10.0.0.0/8; - the provider bother about address translation, just as about name translation (DNS re-writing), just as about the address allocation (not the customer but the provider - if existing address space is not enough); - the providers's software learn about _open, or public_ services which must be translated statically, from the customer using (for example) DNS.

Don't answer _it's too slow_.

This is my attempt to predict where we are going this days. Today the _know-how_ the customer should know is too huge - if (if I am the admin of the company, not ISP!) I open electronic market or want to get Internet for the companies employees, I must allocate space (why? What for? It's not my concern, if we think a little), I must prove I need this addresses (why? This is my business how much addresses I need internally; and let's software decide how much addresses I need externally), and I should configure firewalls and NAT's. We used to think about it as about the normal admin's knowledge; but why we are sure it's normal. If you got a car (in USA, not in the Russia), you don't bother about the oil stations or about the roads - you just use it.

This is not really a dump question. If it is possible to build such Internet service when every customer should be free to use any address space in the hidden way, and ISP (not the customer) bother about the global address and name translation, we should have just this hierarchical address schema IPv6 offer to us. On the other hand, it means a great increase in the NAT engine.

Aleksei Roudnev, Network Operations Center, Relcom, Moscow (+7 095) 194-19-95 (Network Operations Center Hot Line),(+7 095) 230-41-41, N 13729 (pager) (+7 095) 196-72-12 (Support), (+7 095) 194-33-28 (Fax)

++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Plain Aviation, Inc dean@av8.com LAN/WAN/UNIX/NT/TCPIP http://www.av8.com ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

Aleksei Roudnev, Network Operations Center, Relcom, Moscow (+7 095) 194-19-95 (Network Operations Center Hot Line),(+7 095) 230-41-41, N 13729 (pager) (+7 095) 196-72-12 (Support), (+7 095) 194-33-28 (Fax)