Systemd 244 Released With New Init System Features For Black Friday

[starshipeleven]

Glad that Red Hat is fully controlling the path that Linux takes

We couldn't hope for a better benevolent overlord.

[starshipeleven]

Glad that IBM is fully controlling the path that system/Dinux takes

Fixed it for you. Is this the part where Microsoft destroys them like they did with OS/2?

No it all ends with Microsoft buying Canonical and renaming Ubuntu into Microsoft Linux

[bachchain]

Systemd-networkd now retains the DHCP configuration across restarts by default along with various other networkd changes.

Why? Are DHCP requests really that expensive?

[ermo]

Why? Are DHCP requests really that expensive?

It might be useful to try to keep the currently assigned IP address across reboots? In the "Hi, I used to be x.x.x.x, can I have that address again please?" sense.

[Hibbelharry]

It might be useful to try to keep the currently assigned IP address across reboots? In the "Hi, I used to be x.x.x.x, can I have that address again please?" sense.

Thats usually done serverside, not on clients. You just need a cheap and available dhcp client.

[Emmanuel Deloget]

Why? Are DHCP requests really that expensive?

If you ever had a lease, you're supposed to REQUEST an address to a known server, not to DISCOVER the world. While DHCP is not, per see, an expensive protocol, a DISCOVER message is still a broadcast that will prompt for an answer from all DHCP servers that receive it - answer to which the client will reply by a REQUEST. So doing a REQUEST instead is going to be cheaper and faster in all cases.

[bachchain]

If you ever had a lease, you're supposed to REQUEST an address to a known server, not to DISCOVER the world. While DHCP is not, per see, an expensive protocol, a DISCOVER message is still a broadcast that will prompt for an answer from all DHCP servers that receive it - answer to which the client will reply by a REQUEST. So doing a REQUEST instead is going to be cheaper and faster in all cases.

Sure, but the broadcast is local to that network segment, the client only waits for the first response, and there should really only be one DHCP server per segment anyway. So the discovery should only take one round trip and a few milliseconds.

[starshipeleven]

Sure, but the broadcast is local to that network segment, the client only waits for the first response, and there should really only be one DHCP server per segment anyway. So the discovery should only take one round trip and a few milliseconds.

I guess this is a problem for large networks. I think you should avoid broadcasts on large networks if possible.

[andyprough]

Why? Are DHCP requests really that expensive?

$10 for a case at Costco.

[CommunityMember]

Thats usually done serverside, not on clients. You just need a cheap and available dhcp client.

It is slightly more complicated in the real world with larger enterprise and ISP environments, where there are multiple DHCP servers with various failover and/or load sharing configurations, and/or where the lease may have expired, and/or different DHCP server implementations. And in addition, while changing your IP address may not matter for outbound connectivity, if you need to register your new address in DNS for inbound the new association may very well take minutes (or longer, much longer) to propagate through all the caching mechanisms, again, depending on details, in larger real world environments. So *trying* to get the same association as before may not be strictly necessary, it is a useful enhancement.