Alternatives to ISC dhcp-client ?

[Rick Thomas]

According to the ISC webpage:

> ISC has ended development on the ISC DHCP client as of early 2022.
> This client implementation is no longer maintained and should not be
> used in production any longer.

Can anybody recommend a good replacement?
Does anybody know what the Debian PTBs are planning for this?

Thanks!
Rick

[Jeremy Ardley]

On 8/5/22 10:47 am, Rick Thomas wrote:
> ISC has ended development on the ISC DHCP client as of early 2022.
>> This client implementation is no longer maintained and should not be
>> used in production any longer.
> Can anybody recommend a good replacement?
>

I presently use systemd-networkd which provides its own DHCP v4 and v6
clients, and servers if you want.

In my network my dual homed router acts as a dhcp client to the ISP and
gets an IPv4 address and is delegated an IPv6 /56 range.

You can just use systemd-networkd as an IPv4 dhcp client.


--
Jeremy

[Jeremy Ardley]

On 8/5/22 11:14 am, Jeremy Ardley wrote:
>
>
> You can just use systemd-networkd as an IPv4 dhcp client.
>
>

Of note: Using systemd-networkd you should not use NetworkManager or
networking services. I think both use the ISC dhcp client

Of further note, I moved to systemd-networkd precisely because the ISC
dhcp client was badly behaved, and no-one at ISC seemed interested in
fixing it.


--
Jeremy

[Rick Thomas]

> Jeremy

Is systemd-networkd automatically installed by Debian?

I ask because my "testing" and "stable" systems all show isc-dhcp-client as installed and running.

Thanks!
Rick

[Rick Thomas]

Thanks for the heads up!
Can you describe in detail what one needs to do in order to switch over? I.e. what to remove, what to install? What to configure?

Thanks!
Rick

[Jeremy Ardley]

On 8/5/22 11:27 am, Rick Thomas wrote:
> Thanks for the heads up!
> Can you describe in detail what one needs to do in order to switch over? I.e. what to remove, what to install? What to configure?
>
>
>

This is a recent blogpost of mine showing a more complex installation
including IPv6 delegation. If you just do the bits that refer to IPv4 it
should still work.

https://jeremyardley.blogspot.com/2022/04/configuring-systemd-networkd-with.html

--
Jeremy

[Rick Thomas]

> Jeremy

Thanks!
Rick
PS: I'll also do the IPv6 part, because I'm interested in that too.

[john doe]

For a regular installation of Debian, yes.

--
John Doe

[Kamil Jońca]

Jeremy Ardley <jer...@ardley.org> writes:

[...]

>
> You can just use systemd-networkd as an IPv4 dhcp client.

I cannot see if systemd-networkd can run scripts[1] after change in
lease. Am I missing something?

KJ
[1] similar to /etc/dhcp/dhclient*hooks.d
--
http://wolnelektury.pl/wesprzyj/teraz/

[Jeremy Ardley]

On 8/5/22 3:19 pm, Kamil Jońca wrote:
> I cannot see if systemd-networkd can run scripts[1] after change in
> lease. Am I missing something?
>

The top answer below is a partial answer to your question.

https://unix.stackexchange.com/questions/469716/systemd-networkd-run-script-after-dhcp-client-aqcuires-new-address

But systemd-networkd also has a huge number of configuration options
that may do what you want anyway

https://www.freedesktop.org/software/systemd/man/systemd.network.html


> --
Jeremy

[Jeremy Ardley]

On 8/5/22 2:27 pm, Rick Thomas wrote:
> Thanks!
> Rick
> PS: I'll also do the IPv6 part, because I'm interested in that too.
>

One word of caution moving away from ISC dhcp client is that any
possibility of it being started by the networking daemon will result in
very bad behaviour if you have any left-over lease files - whether or
not you have dhcp set in your /etc/network.interfaces file

In that case, the dhcp server will be spammed many times a second by
dhclient.

I'll amend my blog post to stop the networking service, kill any
dhclient processes, and then erase any dhclient lease files

rm -f /var/lib/dhcp/dhclient*


--
Jeremy

[Kamil Jońca]

Jeremy Ardley <jer...@ardley.org> writes:

> On 8/5/22 3:19 pm, Kamil Jońca wrote:
>> I cannot see if systemd-networkd can run scripts[1] after change in
>> lease. Am I missing something?
>>
> The top answer below is a partial answer to your question.
>
> https://unix.stackexchange.com/questions/469716/systemd-networkd-run-script-after-dhcp-client-aqcuires-new-address

You mean:

"I couldn't get networkd-dispatcher to respond to dhcp changes on Ubuntu
Server 20.04, but[...] " :) ?

Yes. I know that this is two year old, but I did not found anything
newer with answer.

>
> But systemd-networkd also has a huge number of configuration options
> that may do what you want anyway
>
> https://www.freedesktop.org/software/systemd/man/systemd.network.html

Hm. Can you create bridge without ports with systemd-networkd?
i.e.

--8<---------------cut here---------------start------------->8---
iface qemu inet static
dns-search myquemudomain
address 192.168.1.1
netmask 255.255.255.0
bridge_ports none #part which I was not able to achieve
--8<---------------cut here---------------end--------------->8---


I still have situation described in
https://lists.debian.org/debian-user/2022/02/msg00118.html

I simply try to look for migration, but it seems that most of testing I
will have to do by myself.

KJ

--
http://stopstopnop.pl/stop_stopnop.pl_o_nas.html

[Rick Thomas]

Does anybody know what the Debian developers plan to do about this change of policy by ISC? I have a feeling it's going to be a problem that will have to be faced reasonably soon.

Rick

[The Wanderer]

I remember reading a discussion on debian-devel recent-ish-ly which
could be relevant. I haven't reviewed it in detail at the moment, but I
think

https://lists.debian.org/debian-devel/2021/09/msg00407.html

would be a good starting point for anyone who does want to review it.

--
The Wanderer

The reasonable man adapts himself to the world; the unreasonable one
persists in trying to adapt the world to himself. Therefore all
progress depends on the unreasonable man. -- George Bernard Shaw

[Stefan Monnier]

Rick Thomas [2022-05-07 19:47:57] wrote:
> According to the ISC webpage:
>> ISC has ended development on the ISC DHCP client as of early 2022.
>> This client implementation is no longer maintained and should not be
>> used in production any longer.
> Can anybody recommend a good replacement?

Depends on your needs, but `busybox` provides a dhcp client that's good
enough for the most common situations.


Stefan

[Dan Ritter]

The package name is udhcpc.

-dsr-

[Oliver Schoede]

Right, it's not (yet?) tagged for provides/dhcp-client but at home
would probably do the trick for me, too. Alternatively there's dhcpcd5,
which is tagged and also specifically mentioned on the ISC's eom-page,
though apparently a much broader solution. I'll be using the
legacy one until it's actually removed from Debian and then switch to
whatever is recommended, if anything and provided it's not networkd.

Oliver


https://roy.marples.name/projects/dhcpcd

[Michael Stone]

On Sun, May 08, 2022 at 04:09:27PM +0200, Oliver Schoede wrote:
>Alternatively there's dhcpcd5,

Be careful with this one unless you have a simple network
configuration--by default it will attempt to get addresses on all
interfaces that don't have them, not only ones you set to dhcp in
/etc/network/interfaces

[john doe]

On 5/8/2022 6:33 PM, Kamil Jońca wrote:
> Kamil Jońca <kjo...@o2.pl> writes:
>
> [...]

>>>
>>> But systemd-networkd also has a huge number of configuration options
>>> that may do what you want anyway
>>>
>>> https://www.freedesktop.org/software/systemd/man/systemd.network.html
>>
>> Hm. Can you create bridge without ports with systemd-networkd?
>> i.e.
>>
>

> Another question. Can I pass option during interface up/down?
> For example, in my if-up*/if-down* scripts I have code for replacing (or
> not!) default route when needed.[1]
>
> Then I can execute something like:
>
> --8<---------------cut here---------------start------------->8---
> ifup wlan0 -o replacedefaultroute=on
> --8<---------------cut here---------------end--------------->8---
>
> how I can achieve this with networkctl (or other systemd tool)?
>
> Moreover https://gitlab.com/craftyguy/networkd-dispatcher/-/issues/61
> So my migration probes are not very promising :/
>
> I take into account that I have some habits and some thing should be
> done completely different way[2]. But for now I even don't know if some
> things can be achieved.
>

You might be better off asking this on the appropriate mailing list! :)

--
John Doe

[Kamil Jońca]

Kamil Jońca <kjo...@o2.pl> writes:

[...]
>>
>> But systemd-networkd also has a huge number of configuration options
>> that may do what you want anyway
>>
>> https://www.freedesktop.org/software/systemd/man/systemd.network.html
>
> Hm. Can you create bridge without ports with systemd-networkd?
> i.e.
>

Another question. Can I pass option during interface up/down?
For example, in my if-up*/if-down* scripts I have code for replacing (or
not!) default route when needed.[1]

Then I can execute something like:

--8<---------------cut here---------------start------------->8---
ifup wlan0 -o replacedefaultroute=on
--8<---------------cut here---------------end--------------->8---

how I can achieve this with networkctl (or other systemd tool)?

Moreover https://gitlab.com/craftyguy/networkd-dispatcher/-/issues/61
So my migration probes are not very promising :/

I take into account that I have some habits and some thing should be
done completely different way[2]. But for now I even don't know if some
things can be achieved.

KJ
[1]
in man systemd.network
I found
--8<---------------cut here---------------start------------->8---
[DHCPV4]
UseRoutes=
--8<---------------cut here---------------end--------------->8---
but I am not sure if this is about default routes or only classless
static routes

[2] - I had to spent some time to "properly" translate my iptables
rules/scripts to nftables ones (using sets and maps instead simple
iptables -I ... nad iptables -D ... command).


--
http://stopstopnop.pl/stop_stopnop.pl_o_nas.html

[Vincent Lefevre]

On 2022-05-08 11:19:33 +0800, Jeremy Ardley wrote:
> Of note: Using systemd-networkd you should not use NetworkManager or
> networking services. I think both use the ISC dhcp client

And what about NetworkManager users?

Note: it has its own internal DHCP client, but it is not robust on
buggy networks:

https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=933930

And the dhclient hooks are not run:

https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=966618

So I don't use it.

In particular, in my /etc/dhcp/dhclient.conf isc-dhcp-client
configuration file, I have

prepend domain-name-servers 127.0.0.1;

to be able to use the local nameserver preferably (the nameservers
provided by the DHCP server are still needed on networks that
filter UDP).

--
Vincent Lefèvre <vin...@vinc17.net> - Web: <https://www.vinc17.net/>
100% accessible validated (X)HTML - Blog: <https://www.vinc17.net/blog/>
Work: CR INRIA - computer arithmetic / AriC project (LIP, ENS-Lyon)

[Anssi Saari]

Dan Ritter <d...@randomstring.org> writes:

> The package name is udhcpc.

Yes, and it's very cool. Well, poorly documented so it was a little hard
to understand. Mostly my problem was the script it wants to run for
various events and how to fix that to do the stuff I need and not do
stuff that messes up my network setup.

But in my case udhcpc seems to be the only DHCP client that will talk to
the LTE module in my router, others just balk and whine.