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I’ll google it in a moment, but skimming those notes, I have no idea what Kea is.
Next gen reference DHCP server. IIRC it's new thing is IPv6 support.
Kea's new thing is scaling up for very large/complex installations (multithreading, database backends, a fair amount of plugins for specialized use cases). Which almost nobody really needs to do, so it's a shame ISC dhcpd was discontinued before Kea was at full feature parity.
Earlier quoted context omitted.
Won't take long, ISC doesn't do 'much' but they do it well
I remember Dan Bernstein (djb) being scathing about BIND. To the extent of writing his own DNS suite. Is that all ancient history now?
It yet again runs as the superuser serving requests from potentially hostile clients. In fairness, a lot of DHCP servers do this; but Kea development was in a position to have learned the ideas about using unprivileged dæmons, having started years later than them. Instead, its documented approach to running as some other account is to add some of the superuser's privileges to Kea, completely missing the point of running large complex programs without privileges, which was a major long-standing criticism of BIND and Sendmail that didn't just come from Daniel J. Bernstein.
* https://kea.readthedocs.io/en/latest/arm/install.html#runnin...
It's interesting that systemd is mentioned there, because a socket unit would have had systemd doing the privileged opening of the sockets with low-numbered UDP ports, and the dropping of privileges, before starting up Kea. But Kea (again, like many of the pre-systemd DHCP servers like the WIDE one or the BusyBox one) opens and listens on sockets itself, and has no attempt at enabling use of systemd's mechanism in this regard.
There is still the old flawed mechanism of PID files liberally sprinkled around, too.
* https://github.com/isc-projects/kea/blob/048b1e9b1acbb0ff962...
And of course, Kea took some of the BIND 10 code. There is a lot of continuation of long standing BIND Think in Kea, alas.
There's so much promise to the idea of having DHCP servers use shared database back-ends, but it's spoiled by all of the continued BIND Think and things like having an HTTP server with JSON parser in all of these superuser-privileged dæmons. One of these days, someone will actually run with the idea that I mentioned somewhen in the early 2000s: a DHCP server that shared a common database with a content DNS server. No notification messages for mapping updates, no little shim dæmons, just serving out the information in the shared database directly, complete with (say) TTLs that match the lease expiry times.
People have danced around this idea for a long time, but never quite fully hit it. PowerDNS can use custom database back ends, for example, but people still have not fully run with that and instead ended up with a DHCP server with a database sending potentially dropped notifications over a terrible protocol to a content DNS server also with its own separate database back end.
* http://tuxad.com/txdyn-doc.html
* https://holland-consulting.net/tech/dhcp-dns.html
* https://github.com/AliveDevil/pdns-dhcp
* https://gitlab.isc.org/isc-projects/kea/-/issues/1409
Microsoft Windows Server's DNS server with AD integration perhaps came the closest, but even with that the out-of-the-box setup had things like DHCP clients sending (some of) the update notifications.
I’ll google it in a moment, but skimming those notes, I have no idea what Kea is.
As others have said, Kea is a DHCP server. More than that, it is an ISC project, is the successor to ISC DHCP (now end-of-life & unsupported for a few years), and weirdly started out as part of BIND 10. Ref: https://www.isc.org/dhcphistory/#the-kea-dhcp-server (And I vaguely recall it's used as the DHCP component in a few other things, like maybe Infoblox).
Earlier quoted context omitted.
I remember Dan Bernstein (djb) being scathing about BIND. To the extent of writing his own DNS suite. Is that all ancient history now?
No. Kea is making several of the same mistakes all over again, despite being in a good position to have learned from them. It yet again runs as the superuser serving requests from potentially hostile clients. In fairness, a lot of DHCP servers do this; but Kea development was in a position to have learned the ideas about using unprivileged dæmons, having started years later than them. Instead, its documented approach…
Can systemd give you the raw sockets you need to answer DHCP on a local network?
One rather annoying thing that ISC dhcpd couldn't do was reload its config file without a full restart (and I believe Kea can). That's pretty hard to do if you insist on someone else opening sockets for you, although you could of course demand a restart in this case.
TBH my problem (well, one of my problems) with Kea is more that it's _too_ many different daemons that you have to configure separately and get to talk to each other, and it's not immediately obvious if any given configuration is secure or not (e.g., can others open a socket of the same name?).
I observe how so many of these kinds of release announcements do not start the text with a brief line introducing the project. I had never heard of Kea and clicked through out of curiosity, but that info is yet another click away: Kea is a "Modern, open source DHCPv4 & DHCPv6 server".
Earlier quoted context omitted.
I remember Dan Bernstein (djb) being scathing about BIND. To the extent of writing his own DNS suite. Is that all ancient history now?
No. Kea is making several of the same mistakes all over again, despite being in a good position to have learned from them. It yet again runs as the superuser serving requests from potentially hostile clients. In fairness, a lot of DHCP servers do this; but Kea development was in a position to have learned the ideas about using unprivileged dæmons, having started years later than them. Instead, its documented approach…
(I'm the author of a JS framework with the same name)
Earlier quoted context omitted.
No. Kea is making several of the same mistakes all over again, despite being in a good position to have learned from them. It yet again runs as the superuser serving requests from potentially hostile clients. In fairness, a lot of DHCP servers do this; but Kea development was in a position to have learned the ideas about using unprivileged dæmons, having started years later than them. Instead, its documented approach…
Does systemd socket activation even work with broadcast packets? One of the things a dhcp server needs to do is respond to DHCPDISCOVER packets, which are sent to the all-broadcast 255.255.255.255 .
Or could do it.
If it weren't that Kea has no mechanism for taking and just using an already-open socket.
Remember that Accept in a socket unit has no meaning for ListenDatagram sockets. There's no waiting for incoming connections before activation going on.
If you're asking about the detailed internals of what systemd does with BPF and how that meshes with what Kea does, then I leave that to be answered by the systemd and Kea people. (-:
I observe how so many of these kinds of release announcements do not start the text with a brief line introducing the project. I had never heard of Kea and clicked through out of curiosity, but that info is yet another click away: Kea is a "Modern, open source DHCPv4 & DHCPv6 server".