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IPv4 Space Shrinks To 5% – Final Addresses To Be Issued In Early 2011

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Re: IPv4 Space Shrinks To 5% – Final Addresses To Be Issued In Early 2011

#51

Post by jfr »

tptacek wrote: post #29
wccrawford wrote: post #2

I don't think my router even supports IPv6. This is going to be -such- a fun transition. I really thought people would get serious about it 2 years ago.

Most of your software doesn't support IPv6, which I think is a bigger problem. Most everything that works with sockets assumes that a network address fits in a machine int type; IPv6 addresses aren't even scalar.

You mentioned twice that IPv6 addresses aren't scalar in this discussion. Why?

Are you talking about the scope identifier or the flow label? The scope identifier is not used by the Network Layer, it is used to disambiguate between addresses in different Data Link Layer outputs by the operating system, but plays no role in routing after the packet leaves the network card. There is no field for it in the IPv6 packet.

The flow label is part of the IPv6 packet, but it is used for routing and quality of service, it is not used for addressing.

So, the IPv6 address is actually just a 128-bit scalar integer, that goes from 0 to 340282366920938463463374607431768211455, with different sub-ranges designated to different purposes.

Re: IPv4 Space Shrinks To 5% – Final Addresses To Be Issued In Early 2011

#52

Post by tptacek »

jfr wrote: post #51
tptacek wrote: post #29

Earlier quoted context omitted.

Most of your software doesn't support IPv6, which I think is a bigger problem. Most everything that works with sockets assumes that a network address fits in a machine int type; IPv6 addresses aren't even scalar.

You mentioned twice that IPv6 addresses aren't scalar in this discussion. Why? Are you talking about the scope identifier or the flow label? The scope identifier is not used by the Network Layer, it is used to disambiguate between addresses in different Data Link Layer outputs by the operating system, but plays no role in routing after the packet leaves the network card. There is no field for it in the IPv6 packet. T…

In very few languages people use today is there a 128 bit scalar integer type. You're right to point out that I'm being imprecise with my terms, but I think now you get what I'm saying.

Re: IPv4 Space Shrinks To 5% – Final Addresses To Be Issued In Early 2011

#53

Post by jfr »

contextfree wrote: post #36
tptacek wrote: post #32

Earlier quoted context omitted.

It is, but not in the way you think. IPv4 addresses are also cognitively nasty (try to remember two of them, walk to the other end of your building, and recite them from memory). People don't often use them directly. The problem is that IPv4 addresses happen to fit in machine registers, and so virtually all of the world's networking software has been written to assume that they are just a gossamer-thin semantic layer…

Do you think it would have been better if they'd gone to a 64-bit format instead of 128-bit?

No way! It took us almost 20 years to start moving towards IPv6, at great costs. It was better to exaggerate on the address space so that to we don't have to bother with another transition for a long, long time. I don't expect the next transition to happen before we start colonizing Alpha Centauri.

Re: IPv4 Space Shrinks To 5% – Final Addresses To Be Issued In Early 2011

#54

Post by tptacek »

jfr wrote: post #53
contextfree wrote: post #36

Earlier quoted context omitted.

Do you think it would have been better if they'd gone to a 64-bit format instead of 128-bit?

No way! It took us almost 20 years to start moving towards IPv6, at great costs. It was better to exaggerate on the address space so that to we don't have to bother with another transition for a long, long time. I don't expect the next transition to happen before we start colonizing Alpha Centauri.

You realize that just like 64 bit addresses presume we'll never have a 18446744073709551616th host, 128 bit addresses presume we'll never have another network layer, right?

Have you considered whether we're putting entirely too much emphasis on whether or not there is an end-to-end "Internet Protocol" Internet with a single coherent address space? Most people don't use Internet addresses. In fact: most people already use an entirely application-intermediated address format: it's called "the first 4 results on a Google SERP".

Re: IPv4 Space Shrinks To 5% – Final Addresses To Be Issued In Early 2011

#55

Post by m_eiman »

randomtask wrote: post #42
m_eiman wrote: post #38

Earlier quoted context omitted.

That works until you're sitting behind another NAT that uses the same internal IP range as the one you connect to over VPN - which is very likely since everyone uses 192.168.0.0/24.

Assuming the VPN server doesn't just allocate from a pool of public IPs owned by the organisation you're connecting into (the scenario I had in mind here) then yes this is an issue.

I'd guess that the NAT+NAT problem is more common than the enterprise variant, since very few companies other than enterprises have more than a few IPs.

Re: IPv4 Space Shrinks To 5% – Final Addresses To Be Issued In Early 2011

#56

Post by TheCondor »

jsz0 wrote: post #10
wccrawford wrote: post #2

I don't think my router even supports IPv6. This is going to be -such- a fun transition. I really thought people would get serious about it 2 years ago.

Devices that don't support IPv6, or don't have IPv6 enabled, will just share an IPV4 address in a NAT pool at the ISP level. It's not pretty but it works.

Sort of. There are some very real limitations what what how much you can NAT too.

Never mind what happens when various services break due to double NATing and the various port filtering, think VOIP and the like. Probably not terribly difficult for a few P2P programs to DoS your ISP wide NAT as well.

Re: IPv4 Space Shrinks To 5% – Final Addresses To Be Issued In Early 2011

#57

Post by rubinelli »

jedbrown wrote: post #15
DeusExMachina wrote: post #11

Earlier quoted context omitted.

Good point. I thought that there is not much use for a public IP for a printer, but I did not think about big address allocations. But is there any convenience in this? Can't they just switch a private LAN infrastructure connected through NAT?

Printing from off-site is easier with a public IP, I don't know how often that is necessary.

I'd wager it's done more often by accident than on purpose.

Re: IPv4 Space Shrinks To 5% – Final Addresses To Be Issued In Early 2011

#58

Post by dasil003 »

tptacek wrote: post #30
demallien wrote: post #22

Earlier quoted context omitted.

It would be a better use of everybody's energy to actually get to work on the IPv6 transition, rather than trying to squeeze another couple of years out of IPv4. I think it should be pretty much obvious to everyone by now that until we actually hit the wall of IPv4, no one is going to get serious about the transition. NAT is not a great solution - it's a hack, and as anybody that has had to set up a server behind a N…

I'll wager that most residential Internet users are NAT'd, as are most corporate Internet users. The Internet works better today than it did back in 1996, when virtually nobody was NAT'd (back then, the big imposition was dynamic addresses instead of static).

NAT'd by their own router you mean? Because that seems like a world of difference from ISP-level NAT which I can imagine breaking a lot of shit.

Re: IPv4 Space Shrinks To 5% – Final Addresses To Be Issued In Early 2011

#59

Post by tptacek »

dasil003 wrote: post #58
tptacek wrote: post #30

Earlier quoted context omitted.

I'll wager that most residential Internet users are NAT'd, as are most corporate Internet users. The Internet works better today than it did back in 1996, when virtually nobody was NAT'd (back then, the big imposition was dynamic addresses instead of static).

NAT'd by their own router you mean? Because that seems like a world of difference from ISP-level NAT which I can imagine breaking a lot of shit.

When people argue that IPv6 is necessary because NAT is a terrible hack that breaks applications, they are talking about the concept of NAT, the thing that makes it hard to pass a callback address in protocols they design and that requires their routers to peek into their FTP traffic.

I'm sure ISP NAT is at some level worse than home NAT, but the point is, we can scale our IPv4 address space if companies stop, for instance, spending /19's to give every one of their desktops a routable IP address (which are then firewalled off the Internet anyways). We'll simply have to accept some form of self-managed NAT to do that.

I'm fine with that. We're freighting IP with too much responsibility and it's holding us back. We'd have multicast in several different service models by now if people would just stop trying to get Cisco IOS routers to do it for us.

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