4 ms·

> This is misleading: computers (and especially printers) attached to a local network do not deplete public IP addresses A device connected to a LAN in someone

> This is misleading: computers (and especially printers) attached to a local network do not deplete public IP addresses A device connected to a LAN in someone's house will often just have a private IP and go through a NAT for its internet access. However many big organisations will have been allocated a large address space at some point, often the size of a Class B. Their machines internally will often use a global IP address. The printers I use at university have their own public IPs. I'm guessing that's not unusual.

DeusExMachina 16y ago
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?
- jedbrown 16y ago
  Printing from off-site is easier with a public IP, I don't know how often that is necessary.
  - randomtask 16y ago
    This would be better done with a VPN than simply allowing external access to your printers.
    - m_eiman 16y ago
      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.
      - randomtask 16y ago
        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.
        m_eiman 16y ago
        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.
  - rubinelli 16y ago
    I'd wager it's done more often by accident than on purpose.
- randomtask 16y ago
  > Can't they just switch a private LAN infrastructure connected through NAT? They could and given that in most organisations devices are already generally subject to restrictive firewall rules it shouldn't impact them all that much. I think it would be better to focus efforts on making these organisations move to IPv6. This could possibly be achieved by ordering them to give back most of their IPv4 addresses. Since they will then be forced to reorganise their infrastructure anyway they could use this opportunity to switch on IPv6 across their organisation at the same time, if they haven't already.
  - Kadin 16y ago
    > This could possibly be achieved by ordering them to give back most of their IPv4 addresses. That would take years and cost millions of dollars, just for the lawyers. New address allocations make it clear that you're really only being loaned the addresses -- but the old allocations didn't. Insofar as you can "own" a bunch of addresses, the companies and organizations with legacy allocations really do own them, and I suspect many of them (the ones that haven't voluntarily given them up already) probably aren't interested in giving them up and might decide to fight back. Look over a list of Class As and tell me which you'd like to take on in court. Obviously they could be bribed into giving those addresses up, if someone wanted to cover the cost of switching ... but if you're going to spend the money, there are probably better things you could do to spur IPv6 adoption than spend it on corporate networks with a well-defined upgrade policy. You'd probably do better to work with the big residential ISPs, or maybe with the wireless carriers, since that's where a lot of the new demand growth is. The legacy allocation ship sailed a long time ago, and there are better things we can do now than try to chase it down and board it by force.
- Kadin 16y ago
  If they have the allocation, why wouldn't they use it? That's how IP was supposed to work. And once you've worked in a network where everyone has a real, non-RFC1918 address, you'll probably not want to go back. It just makes things really convenient; you never need to worry about address space collisions if you decide to connect two building networks together, for instance ... it's a whole lot more elegant than private addressing. The places I've worked at that have legacy allocations have absolutely no interest in switching to RFC1918, and their allocation agreements are old enough that they don't contain any clawback provisions. It'll be "from my cold, dead hands" before they transition, and I can't blame them. It's how the Internet was supposed to work. It's unfortunate that IPv6 got used as a way to shoehorn in a lot of stuff besides just increasing the address space. I've periodically seen much more conservative proposals that would have been less of a "forklift upgrade" and I think in retrospect it's unfortunate that these weren't considered. But if IPv6 manages to kill or at least discourage the widespread use of RFC1918 addresses and bring back a more peer-to-peer architecture, it will be worth it in the long haul. The variety of applications and use cases we would be killing off without even knowing it by continuing down the path towards multiple layers of private addresses (because they just wouldn't be possible under that topology, and hence would never get developed) ought to sober anyone interested in development and new technology. It may be possible for the Internet of today to work just fine with ISP-level NAT on top of home-network NAT, but if we resign ourselves to that we're shutting out a whole lot of interesting future possibilities that can only happen with an Internet that has end-to-end routability without second-class citizens. That would be truly sad.

DeusExMachina 16y ago

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?

jedbrown 16y ago
Printing from off-site is easier with a public IP, I don't know how often that is necessary.
- randomtask 16y ago
  This would be better done with a VPN than simply allowing external access to your printers.
  - m_eiman 16y ago
    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.
    - randomtask 16y ago
      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.
      - m_eiman 16y ago
        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.
- rubinelli 16y ago
  I'd wager it's done more often by accident than on purpose.
randomtask 16y ago
> Can't they just switch a private LAN infrastructure connected through NAT? They could and given that in most organisations devices are already generally subject to restrictive firewall rules it shouldn't impact them all that much. I think it would be better to focus efforts on making these organisations move to IPv6. This could possibly be achieved by ordering them to give back most of their IPv4 addresses. Since they will then be forced to reorganise their infrastructure anyway they could use this opportunity to switch on IPv6 across their organisation at the same time, if they haven't already.
- Kadin 16y ago
  > This could possibly be achieved by ordering them to give back most of their IPv4 addresses. That would take years and cost millions of dollars, just for the lawyers. New address allocations make it clear that you're really only being loaned the addresses -- but the old allocations didn't. Insofar as you can "own" a bunch of addresses, the companies and organizations with legacy allocations really do own them, and I suspect many of them (the ones that haven't voluntarily given them up already) probably aren't interested in giving them up and might decide to fight back. Look over a list of Class As and tell me which you'd like to take on in court. Obviously they could be bribed into giving those addresses up, if someone wanted to cover the cost of switching ... but if you're going to spend the money, there are probably better things you could do to spur IPv6 adoption than spend it on corporate networks with a well-defined upgrade policy. You'd probably do better to work with the big residential ISPs, or maybe with the wireless carriers, since that's where a lot of the new demand growth is. The legacy allocation ship sailed a long time ago, and there are better things we can do now than try to chase it down and board it by force.
Kadin 16y ago
If they have the allocation, why wouldn't they use it? That's how IP was supposed to work. And once you've worked in a network where everyone has a real, non-RFC1918 address, you'll probably not want to go back. It just makes things really convenient; you never need to worry about address space collisions if you decide to connect two building networks together, for instance ... it's a whole lot more elegant than private addressing. The places I've worked at that have legacy allocations have absolutely no interest in switching to RFC1918, and their allocation agreements are old enough that they don't contain any clawback provisions. It'll be "from my cold, dead hands" before they transition, and I can't blame them. It's how the Internet was supposed to work. It's unfortunate that IPv6 got used as a way to shoehorn in a lot of stuff besides just increasing the address space. I've periodically seen much more conservative proposals that would have been less of a "forklift upgrade" and I think in retrospect it's unfortunate that these weren't considered. But if IPv6 manages to kill or at least discourage the widespread use of RFC1918 addresses and bring back a more peer-to-peer architecture, it will be worth it in the long haul. The variety of applications and use cases we would be killing off without even knowing it by continuing down the path towards multiple layers of private addresses (because they just wouldn't be possible under that topology, and hence would never get developed) ought to sober anyone interested in development and new technology. It may be possible for the Internet of today to work just fine with ISP-level NAT on top of home-network NAT, but if we resign ourselves to that we're shutting out a whole lot of interesting future possibilities that can only happen with an Internet that has end-to-end routability without second-class citizens. That would be truly sad.