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Comment by rurban | Hacker News Reader

> The static lease DHCP server logic in systemd-networkd may now serve IP addresses outside of the configured IP pool range for the server.

See, see, taking lessons from C++. So someone requested a bug, and they got it. How could that be useful?

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Suppose you have a network 192.168.0.0/24, with the router at 192.168.0.1, and you want the DHCP server to hand out dynamic addresses from 192.168.0.50 to 192.168.0.240 to clients, and hand out static IPs from 192.168.0.2 to 192.168.0.49 to specific identified devices via static leases. Those static IPs are outside the configured IP range for the DHCP server, intentionally.

DHCP protocol actively avoids specifying a policy - that is for the system administrator. It defines three 'mechanisms' for allocation [0]:

  * automatic == permanent address
  * dynamic == finite (time-limited) and possibly re-assignable to a different client
  * manual == assigned by system administrator (and simply conveyed by DHCP)

Static leases outside any 'pool' are "manual" allocations.

[0] https://datatracker.ietf.org/doc/html/rfc2131#section-1

I think there’s a misunderstanding. The [DHCPServer] section is tied to a [Network] unit. The [Network] unit has an address range. The [DHCPServer] section has options to reserve a range for dynamic leases. There is also [DHCPServerStaticLease] sections to assign static leases. However, previous versions of networkd did not allow the static lease to be outside of the [DHCPServer] dynamic range. Now, the static lease can be outside the dynamic range but within the network range. So, pretty much what any other standard DHCP server can do.

wait, hang on - the init process now incorporates a dhcp server? why? when there are existing solutions to that problem?

no, it's not the init process, it's one of the tools in the systemd suite

Systemd is a matryoshka doll of bugs.

How could that be useful?

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