4 ms·

If an organization ever had the technical control over their network to make 240.0.0.0/4 usable, why would they not use IPv6 instead?

bell-cot 2y ago
An org with that level of technical control might well be an extremely security-conscious org. And "No IPv6 Anywhere, Ever" would make it somewhat easier to keep things secure.
- phildenhoff 2y ago
  Ah, for the companies with high technical control, but no technical competence! Of course :)
  - bell-cot 2y ago
    If your #1 goal is to keep the stuff you manage secure, then keeping that stuff as simple as practical is a pretty obvious strategy. If your #1 goal is to keep your 133t bragging rights, then there are no such things as unnecessary nor excessive complexities.
    - zokier 2y ago
      A brick is very simple and very secure. Some might say practically unhackable.
      - bell-cot 2y ago
        True. But if you need a secure network for the factory's SCADA equipment - a brick is just not a practical substitute.
DaSHacka 2y ago
It would presume its significantly easier to implement routing for a few more blocks of IPv4 addresses than switch the entire underlying infrastructure to IPv6, which requires different infrastructure than IPv4 to work properly (like dealing with SLAAC/DHCPv6 addresses, ICMP, and AAAA addresses)
omoikane 2y ago
They might have to interact with a lot of devices that only support IPv4, and will never upgrade. These include a lot of industrial PLCs and various embedded devices. 10.0.0.0/8 might seem like a lot of addresses, but certain large companies have enough fans and chillers and miscellaneous things that can fill that space, and it takes a lot of effort to reorganize their network to better allocate those addresses.
- helf 2y ago
  Sadly I'm in that position. I have hundreds of PLCs and legacy controllers on my network that are IPv4 only and will never be replaced. At least not in a reasonable time frame. I'm talking 20+ year life expectancies.
- michaelt 2y ago
  > 10.0.0.0/8 might seem like a lot of addresses, but certain large companies have enough fans and chillers and miscellaneous things that can fill that space Do these large companies really have 16,777,216 fans and chillers? That would be enough for each of Wal-Mart's 10,586 stores to have 1500 IPs each. Or do they just have legacy allocation mistakes?
  - omoikane 2y ago
    > Do these large companies really have 16,777,216 fans and chillers? Some of those might be regular servers or networking gear that are required to have IPv4 addresses for one reason or another. For example, they might need to interact with fans and chillers. > legacy allocation mistakes Requiring the same globally unique prefix for devices that share locations or functions would eat up allocations faster than the number devices would grow. But there are definitely good reasons for allocating addresses that way, just as there are probably good reasons why the number of ports on a switch isn't always a power of 2.
  - Control8894 2y ago
    Sometimes they might have been able to allocate it more compactly - but how do you predict exactly what your needs will be in 20 years? Other times they might not have been able to allocate it more compactly - are you really going to go make routes for a /25 and a /26 and a /27 when you need 200 IPs, just to save a single /27 over giving it the whole /24? There can also be reasons to structure it more sparsely than required for UX, namely to give a more hierarchical structure - maybe by region and store, or similar. tl;dr it's not necessarily a mistake that your allocations mean you use more space than strictly necessary
sambazi 2y ago
amazon is using class-e internally for some years now; i guess it's profitable

bell-cot 2y ago

An org with that level of technical control might well be an extremely security-conscious org. And "No IPv6 Anywhere, Ever" would make it somewhat easier to keep things secure.

phildenhoff 2y ago
Ah, for the companies with high technical control, but no technical competence! Of course :)
- bell-cot 2y ago
  If your #1 goal is to keep the stuff you manage secure, then keeping that stuff as simple as practical is a pretty obvious strategy. If your #1 goal is to keep your 133t bragging rights, then there are no such things as unnecessary nor excessive complexities.
  - zokier 2y ago
    A brick is very simple and very secure. Some might say practically unhackable.
    - bell-cot 2y ago
      True. But if you need a secure network for the factory's SCADA equipment - a brick is just not a practical substitute.

DaSHacka 2y ago

It would presume its significantly easier to implement routing for a few more blocks of IPv4 addresses than switch the entire underlying infrastructure to IPv6, which requires different infrastructure than IPv4 to work properly (like dealing with SLAAC/DHCPv6 addresses, ICMP, and AAAA addresses)

omoikane 2y ago

They might have to interact with a lot of devices that only support IPv4, and will never upgrade. These include a lot of industrial PLCs and various embedded devices. 10.0.0.0/8 might seem like a lot of addresses, but certain large companies have enough fans and chillers and miscellaneous things that can fill that space, and it takes a lot of effort to reorganize their network to better allocate those addresses.

helf 2y ago
Sadly I'm in that position. I have hundreds of PLCs and legacy controllers on my network that are IPv4 only and will never be replaced. At least not in a reasonable time frame. I'm talking 20+ year life expectancies.
michaelt 2y ago
> 10.0.0.0/8 might seem like a lot of addresses, but certain large companies have enough fans and chillers and miscellaneous things that can fill that space Do these large companies really have 16,777,216 fans and chillers? That would be enough for each of Wal-Mart's 10,586 stores to have 1500 IPs each. Or do they just have legacy allocation mistakes?
- omoikane 2y ago
  > Do these large companies really have 16,777,216 fans and chillers? Some of those might be regular servers or networking gear that are required to have IPv4 addresses for one reason or another. For example, they might need to interact with fans and chillers. > legacy allocation mistakes Requiring the same globally unique prefix for devices that share locations or functions would eat up allocations faster than the number devices would grow. But there are definitely good reasons for allocating addresses that way, just as there are probably good reasons why the number of ports on a switch isn't always a power of 2.
- Control8894 2y ago
  Sometimes they might have been able to allocate it more compactly - but how do you predict exactly what your needs will be in 20 years? Other times they might not have been able to allocate it more compactly - are you really going to go make routes for a /25 and a /26 and a /27 when you need 200 IPs, just to save a single /27 over giving it the whole /24? There can also be reasons to structure it more sparsely than required for UX, namely to give a more hierarchical structure - maybe by region and store, or similar. tl;dr it's not necessarily a mistake that your allocations mean you use more space than strictly necessary

sambazi 2y ago

amazon is using class-e internally for some years now; i guess it's profitable