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Such a ridiculous complaint, after all, it's not like there's a worldwide shortage of non-routable IPs. Just make your network address space large enough that y

Such a ridiculous complaint, after all, it's not like there's a worldwide shortage of non-routable IPs. Just make your network address space large enough that your DHCP server is rarely, if ever, reassigning the same IP address more than once. I see so many network operators desperate to "right size" their IP ranges when they could just allocate a /18 or /16 or even larger. Microsoft and Apple might not be following the DHCP spec correctly, but they're breaking it for the right reasons. Offering very long lease times is one way to increase apparent network responsiveness to your end users. Give devices an IP address for weeks or even months if you can. Why not?

londons_explore 4y ago
Lots of routers start choking when they have more than a few thousand DHCP leases. Often, they do compute hungry things periodically with every entry in the DHCP lease table - like for example tracking download and upload bandwidth and bytes transferred per client every second using some low performance python script. This has become especially bad since most devices started using a new mac address for every connection. It means an apple device going in and out of range of a wifi point all night can easily create thousands of leases, all active for 7 days or whatever the default (and often unconfigurable) lease time is. You soon run out of IP's, and even if you don't, you run into the aformentioned performance issues.
- oarsinsync 4y ago
  > Lots of routers start choking when they have more than a few thousand DHCP leases. You don’t need to run DHCP services on your router. If you’re running large infrastructure, arguably, you shouldn’t, and should instead run a DHCP server on a server, and leave your router’s resources for routing. > This has become especially bad since most devices started using a new mac address for every connection. It means an apple device going in and out of range of a wifi point all night can easily create thousands of leases Apple MAC address privacy generates a random MAC per SSID. It doesn’t generate a new random MAC every time it reconnects to the same SSID. This would be pretty terrible as far as user experience goes too if they did.
  - londons_explore 4y ago
    > It doesn’t generate a new random MAC every time it reconnects to the same SSID. By default, it does. That's to prevent people like McDonald's tracking your device from restaurant to restaurant as they all have the same SSID
    - neilalexander 4y ago
      Details on the Apple implementation: https://support.apple.com/en-gb/HT211949 https://support.apple.com/en-gb/HT211949 In short, Wi-Fi scans use a randomised MAC, connections to a known network can reuse the same private MAC for up to 6 weeks, can fall back to the device MAC if all else fails.
- simondotau 4y ago
  > Lots of routers start choking when they have more than a few thousand DHCP leases. If someone is running a network of that scale with a dinky little router that chokes at the prospect of remembering a few thousand leases, DHCP really is the least of their problems. > an apple device going in and out of range of a wifi point all night can easily create thousands of leases, all active for 7 days or whatever the default (and often unconfigurable) lease time is. This doesn't happen. That's not how it works. > You soon run out of IP's "Running out" of non-routable IPs isn't a risk, it's a choice.
serf 4y ago
>Why not? parent said it caused network issues at their university. pretty cut & dry 'why not?' included. >Microsoft and Apple might not be following the DHCP spec correctly, but they're breaking it for the right reasons. these groups are both large enough to influence whatever specs they need to without out-right breaking them, in many ways they're the ones least responsible in doing so, as they often times shape the specifications themselves. If they need the spec to include arbitrarily long leases let's ask them to propose that to the spec rather than being OK with certain groups violating things. Violated specs is exactly the kind of thing that that trickles down to unintended and unexpected user experience.
- simondotau 4y ago
  > parent said it caused network issues at their university. No, the parent's university's apparent problem was that their DHCP was reallocating IP addresses soon after expiry. Dramatically increasing the pool size and the lease time wasn't the problem, it's the solution.
  - freedomben 4y ago
    You're not wrong, but I'm saddened at this attitude. IMHO the tech giants already have so much power/ability to shape/force the standards to suit their own practices. The attitude of "Apple should be able to violate the standard all they want and it should be on network operators to accommodate them" is wildly empowering to the elephant over the ant.

londons_explore 4y ago

Lots of routers start choking when they have more than a few thousand DHCP leases. Often, they do compute hungry things periodically with every entry in the DHCP lease table - like for example tracking download and upload bandwidth and bytes transferred per client every second using some low performance python script. This has become especially bad since most devices started using a new mac address for every connection. It means an apple device going in and out of range of a wifi point all night can easily create thousands of leases, all active for 7 days or whatever the default (and often unconfigurable) lease time is. You soon run out of IP's, and even if you don't, you run into the aformentioned performance issues.

oarsinsync 4y ago
> Lots of routers start choking when they have more than a few thousand DHCP leases. You don’t need to run DHCP services on your router. If you’re running large infrastructure, arguably, you shouldn’t, and should instead run a DHCP server on a server, and leave your router’s resources for routing. > This has become especially bad since most devices started using a new mac address for every connection. It means an apple device going in and out of range of a wifi point all night can easily create thousands of leases Apple MAC address privacy generates a random MAC per SSID. It doesn’t generate a new random MAC every time it reconnects to the same SSID. This would be pretty terrible as far as user experience goes too if they did.
- londons_explore 4y ago
  > It doesn’t generate a new random MAC every time it reconnects to the same SSID. By default, it does. That's to prevent people like McDonald's tracking your device from restaurant to restaurant as they all have the same SSID
  - neilalexander 4y ago
    Details on the Apple implementation: https://support.apple.com/en-gb/HT211949 https://support.apple.com/en-gb/HT211949 In short, Wi-Fi scans use a randomised MAC, connections to a known network can reuse the same private MAC for up to 6 weeks, can fall back to the device MAC if all else fails.
simondotau 4y ago
> Lots of routers start choking when they have more than a few thousand DHCP leases. If someone is running a network of that scale with a dinky little router that chokes at the prospect of remembering a few thousand leases, DHCP really is the least of their problems. > an apple device going in and out of range of a wifi point all night can easily create thousands of leases, all active for 7 days or whatever the default (and often unconfigurable) lease time is. This doesn't happen. That's not how it works. > You soon run out of IP's "Running out" of non-routable IPs isn't a risk, it's a choice.

serf 4y ago

>Why not? parent said it caused network issues at their university. pretty cut & dry 'why not?' included. >Microsoft and Apple might not be following the DHCP spec correctly, but they're breaking it for the right reasons. these groups are both large enough to influence whatever specs they need to without out-right breaking them, in many ways they're the ones least responsible in doing so, as they often times shape the specifications themselves. If they need the spec to include arbitrarily long leases let's ask them to propose that to the spec rather than being OK with certain groups violating things. Violated specs is exactly the kind of thing that that trickles down to unintended and unexpected user experience.

simondotau 4y ago
> parent said it caused network issues at their university. No, the parent's university's apparent problem was that their DHCP was reallocating IP addresses soon after expiry. Dramatically increasing the pool size and the lease time wasn't the problem, it's the solution.
- freedomben 4y ago
  You're not wrong, but I'm saddened at this attitude. IMHO the tech giants already have so much power/ability to shape/force the standards to suit their own practices. The attitude of "Apple should be able to violate the standard all they want and it should be on network operators to accommodate them" is wildly empowering to the elephant over the ant.