Hello all,

Using bullseye lite (terminal only) and DHCP (dhclient) I'm trying to
configure two network interfaces, connected to different networks with their
own routers.

I would like to configure one or both of the eth? interfaces as a LAN only
connection, meaning without a "default gateway" and/or DNS server adresses
and such.

I've found some information about what to edit in /etc/dhcp/dhclient.conf,
but after rebooting and checking the output of "route" I still see a
"gateway" entry for eth1.

Does anybody know what to add/remove/change in that dhclient.conf file to
get it to work ?

Remark: I've also seen suggestions to just give eth1 a high metric (so the
eth0 gateway is considered first), but that doesn't work for me as eth0
might not be always available.

Regards,
Rudy Wieser

On 24/04/2023 11:48, R.Wieser wrote:
> Hello all,
>
> Using bullseye lite (terminal only) and DHCP (dhclient) I'm trying to
> configure two network interfaces, connected to different networks with their
> own routers.
>
> I would like to configure one or both of the eth? interfaces as a LAN only
> connection, meaning without a "default gateway" and/or DNS server adresses
> and such.
>
> I've found some information about what to edit in /etc/dhcp/dhclient.conf,
> but after rebooting and checking the output of "route" I still see a
> "gateway" entry for eth1.
>
> Does anybody know what to add/remove/change in that dhclient.conf file to
> get it to work ?
>
> Remark: I've also seen suggestions to just give eth1 a high metric (so the
> eth0 gateway is considered first), but that doesn't work for me as eth0
> might not be always available.
>
> Regards,
> Rudy Wieser
>
>

Do you use NetworkManager? Or dhclient directly? Systemd?

This gives suggestions for both NM and dhclient:
https://unix.stackexchange.com/questions/399659/how-to-avoid-dhclient-default-gateway-on-an-interface

However systemd doesn't use dhclient.conf (I am told). See here:
https://serverfault.com/questions/674731/multiple-dhcp-uplinks-how-to-ignore-dns-and-default-route-on-all-but-one
Last answer mentions systemd.

HIH

--
Chris Elvidge
England

Chris,

> Do you use NetworkManager? Or dhclient directly? Systemd?

I tried "nmcli" but got the response that NetworkManager wasn't running.

I do have a /etc/dhcp/dhclient.conf file, but I'm not sure at all if its
actually used (editing it doesn't seem to change anything).

As for systemd ? It looks like it, as I have a "/etc/systemd" folder.

So, I've got two outof three, with one maybe.

> This gives suggestions for both NM and dhclient:
> https://unix.stackexchange.com/questions/399659/how-to-avoid-dhclient-default-gateway-on-an-interface

Thats one of the links I found from which I applied the "Another way:
dhclient.conf" suggstion. Alas, I still got a "default gateway" on eth1.

> However systemd doesn't use dhclient.conf (I am told). See here:
> https://serverfault.com/questions/674731/multiple-dhcp-uplinks-how-to-ignore-dns-and-default-route-on-all-but-one

Yep, found that one too. The second post (by Nils Toedtmann) says the same
as your link. :-)

> Last answer mentions systemd.

I read that too, but although I can find the "/etc/systemd/network" folder
itself I simply do not have enough information to be sure what the
"*.interface" name should be. Next to that I do not see, under "[DHCP]",
any mentioning of a gateway, but to see the "lets use a high metric" hack
that I, as mentioned, can't use. :-\

In short, the presence of a "dhclient.conf" *and* "/etc/systemd" makes me
quite unsure which one actually gouverns the network configuration. Hence
my post.

Regards,
Rudy Wieser

On 24/04/2023 13:59, R.Wieser wrote:
> Chris,
>
>> Do you use NetworkManager? Or dhclient directly? Systemd?
>
> I tried "nmcli" but got the response that NetworkManager wasn't running.

OK, no NetworkManager.

>
> I do have a /etc/dhcp/dhclient.conf file, but I'm not sure at all if its
> actually used (editing it doesn't seem to change anything).
>
> As for systemd ? It looks like it, as I have a "/etc/systemd" folder.
>
> So, I've got two outof three, with one maybe.
>
>> This gives suggestions for both NM and dhclient:
>> https://unix.stackexchange.com/questions/399659/how-to-avoid-dhclient-default-gateway-on-an-interface
>
> Thats one of the links I found from which I applied the "Another way:
> dhclient.conf" suggstion. Alas, I still got a "default gateway" on eth1.
>
>> However systemd doesn't use dhclient.conf (I am told). See here:
>> https://serverfault.com/questions/674731/multiple-dhcp-uplinks-how-to-ignore-dns-and-default-route-on-all-but-one
>
> Yep, found that one too. The second post (by Nils Toedtmann) says the same
> as your link. :-)
>
>> Last answer mentions systemd.
>
> I read that too, but although I can find the "/etc/systemd/network" folder
> itself I simply do not have enough information to be sure what the
> "*.interface" name should be. Next to that I do not see, under "[DHCP]",
> any mentioning of a gateway, but to see the "lets use a high metric" hack
> that I, as mentioned, can't use. :-\
>
> In short, the presence of a "dhclient.conf" *and* "/etc/systemd" makes me
> quite unsure which one actually gouverns the network configuration. Hence
> my post.
>
> Regards,
> Rudy Wieser
>
>

Are you sure you're using dhclient?
What does `ps ax | grep dhc` say?

Just looked at my 11.6 install. It uses dhcpcd

If yours does too, try putting

interface eth1
nogateway

at the end of /etc/dhcpcd.conf

--
Chris Elvidge
England

Chris,

> Are you sure you're using dhclient?

Reasonably sure : I used

/var/log/syslog | grep -Ei 'dhcp'.

(https://superuser.com/questions/944687/how-to-see-what-dhcp-client-does)

to check, and had a number of lines mentioning "dhcpcd" with one of them
mentioning "adding default route", showing the IP of the router servicing
the eth1 LAN

> What does `ps ax | grep dhc` say?

It says

/user/sbin/dhcpcd -w -q

> Just looked at my 11.6 install. It uses dhcpcd

Could you tell me how you checked that ?

> If yours does too, try putting
>
> interface eth1
> nogateway
>
> at the end of /etc/dhcpcd.conf

That does seem to have done the trick. Thanks.

It also means I have to do a bit more googeling, but now focussed on that
paricular file.

A question though : if that file is there to configure the interfaces, what
than is the "/etc/dhcp/dhclient.conf" file about ? Do you know ?

And strangely enough, I've only seen that "dhcpcd.conf" file being mentioned
once,

https://raspberrypi.stackexchange.com/questions/127497/how-to-setup-eth1-with-fixed-ip

but must admit I skipped it as it was talking about setting a fixed IP.

Regards,
Rudy Wieser

On 24/04/2023 17:34, R.Wieser wrote:
> Chris,
>
>> Are you sure you're using dhclient?
>
> Reasonably sure : I used
>
> /var/log/syslog | grep -Ei 'dhcp'.
>
> (https://superuser.com/questions/944687/how-to-see-what-dhcp-client-does)
>
> to check, and had a number of lines mentioning "dhcpcd" with one of them
> mentioning "adding default route", showing the IP of the router servicing
> the eth1 LAN
>
>> What does `ps ax | grep dhc` say?
>
> It says
>
> /user/sbin/dhcpcd -w -q

that's the line from /usr/lib/systemd/system/dhcpcd.service

>
>> Just looked at my 11.6 install. It uses dhcpcd
>
> Could you tell me how you checked that ?

ps ax | grep dhc

>
>> If yours does too, try putting
>>
>> interface eth1
>> nogateway
>>
>> at the end of /etc/dhcpcd.conf
>
> That does seem to have done the trick. Thanks.
>
> It also means I have to do a bit more googeling, but now focussed on that
> paricular file.
>
> A question though : if that file is there to configure the interfaces, what
> than is the "/etc/dhcp/dhclient.conf" file about ? Do you know ?

it is to configure dhclient

>
> And strangely enough, I've only seen that "dhcpcd.conf" file being mentioned
> once,
>
> https://raspberrypi.stackexchange.com/questions/127497/how-to-setup-eth1-with-fixed-ip

that's coz raspbian uses dhcpcd

>
> but must admit I skipped it as it was talking about setting a fixed IP.
>
> Regards,
> Rudy Wieser
>
>
>

dhclient and dhcpcd are 2 *different* methods of automatically assigning
ip adresses. dhclient is not used by stock raspbian.

look at /usr/lib/systemd/system/dhcpcd.service
systemctl status dhcpcd.service

--
Chris Elvidge
England

Chris,

>> A question though : if that file is there to configure the interfaces,
>> what than is the "/etc/dhcp/dhclient.conf" file about ? Do you know ?
>
> it is to configure dhclient

:-) That much I already assumed.

> dhclient and dhcpcd are 2 *different* methods

Well, that explains everything. I've been focussing on and modifying an
unused configuration file. No wonder nothing seemed to work. :-(

I must say that I don't quite understand why bullseye *lite* would carry two
seperate network configuration methods - one of which it doesn't even use -
while not bothering to including supporting files for when someone (like me)
wants to do a bit of GPIO or graphics using GCC.

>> And strangely enough, I've only seen that "dhcpcd.conf" file being
>> mentioned
>> once,
>>
>> https://raspberrypi.stackexchange.com/questions/127497/how-to-setup-eth1-with-fixed-ip
>
> that's coz raspbian uses dhcpcd

I've seen post about dhcpcd dated as far back as 2011. I would have expected
that my two/three day stint googeling would have popped up that name a few
more times - Especially in relation to the RPi by people having a similar
"how to configure the network" problem.

Than again, how many people would want to create a "LAN only" interface ...

> look at /usr/lib/systemd/system/dhcpcd.service

Thanks. I just did. Can't say I understand what whats in it means though.
More to google I guess. :-)

> systemctl status dhcpcd.service

Apart from recognising the the syslog entries at the bottom the same goes
here.

Thanks for the help and info.

Regards,
Rudy Wieser

On 24/04/2023 19:27, R.Wieser wrote:
> Chris,
>
>>> A question though : if that file is there to configure the interfaces,
>>> what than is the "/etc/dhcp/dhclient.conf" file about ? Do you know ?
>>
>> it is to configure dhclient
>
> :-) That much I already assumed.
>
>> dhclient and dhcpcd are 2 *different* methods
>
> Well, that explains everything. I've been focussing on and modifying an
> unused configuration file. No wonder nothing seemed to work. :-(
>
> I must say that I don't quite understand why bullseye *lite* would carry two
> seperate network configuration methods - one of which it doesn't even use -
> while not bothering to including supporting files for when someone (like me)
> wants to do a bit of GPIO or graphics using GCC.
>

I haven't come across any distro that doesn't include both.
I've always thought the lite moniker just meant no X

>>> And strangely enough, I've only seen that "dhcpcd.conf" file being
>>> mentioned
>>> once,
>>>
>>> https://raspberrypi.stackexchange.com/questions/127497/how-to-setup-eth1-with-fixed-ip
>>
>> that's coz raspbian uses dhcpcd
>
> I've seen post about dhcpcd dated as far back as 2011. I would have expected
> that my two/three day stint googeling would have popped up that name a few
> more times - Especially in relation to the RPi by people having a similar
> "how to configure the network" problem.
>
> Than again, how many people would want to create a "LAN only" interface ...

I do it regularly!

If I'd looked at my installation earlier I'd probably have twigged you
were using dhcpcd not dhclient.

>
>> look at /usr/lib/systemd/system/dhcpcd.service
>
> Thanks. I just did. Can't say I understand what whats in it means though.
> More to google I guess. :-)

The Exec line says what it does - starts dhcpcd. Type say it forks and
Restart tells it to restart if it crashes or is stopped.

The rest of the file just sets up the environment.

>
>> systemctl status dhcpcd.service
>
> Apart from recognising the the syslog entries at the bottom the same goes
> here.
>
> Thanks for the help and info.
>
> Regards,
> Rudy Wieser
>
>
>

--
Chris Elvidge
England

Chris,

> I've always thought the lite moniker just meant no X

My own assumption went a bit further than that : minimal default installed
software, less stuff running by default. Which fit me just fine, as I'm
using it on am ancient, rather slow RPi v1. (yes, I did try to tun a
graphical environment first. It was painfull. :-) )

> If I'd looked at my installation earlier I'd probably have twigged you
> were using dhcpcd not dhclient.

I did see the "dhcpcd" name in the syslog, but as I didn't (yet) know about
whats what I failed to recognise it for what it was ...

A new question though (if you don't mind) : I've been trying to disable ipv6
too, and reading the man page for dhcpcd.conf I saw that I could use
"ipv4only".

I've put that just above the "interface eth1" line (assuming that it would
than work for all interfaces), but "ifconfig" still shows ipv6 adresses for
both "eth1" as well as "lo" (eth0 is disconnected). I also tried to put it
under "interface eth1" and got the same result. As such I'm not at all sure
what that "ipv4only" is supposed to do (if anything).

I get the feeling (fuelled by some googeling results) that ipv6 needs to be
disabled elsewhere. But although googeling for a way to do so turns up some
results, I'm not at all sure if any of it applies to bullseye (most of it is
old).

Besides that, I would also would like to have some more information about
(possibly) disabeling/changing DNS and other stuff dhpdcd seems to ask the
dhcp server for* (even when DNS servers can't be reached without a default
gateway).

* I had a windows machine capture both the request as well as the response.
The RPi asked for a lot, but got only a little ...

In short : do you know of any source of info (website) which explains the
network configuration, focussed on what is currently used by bullseye ?

Regards,
Rudy Wieser

On 26/04/2023 08:20, R.Wieser wrote:
> Besides that, I would also would like to have some more information about
> (possibly) disabeling/changing DNS and other stuff dhpdcd seems to ask the
> dhcp server for* (even when DNS servers can't be reached without a default
> gateway).
DHCP is a noddy default setup for a client machine that is connected to
well maintained environment. If you want other than the defaults I would
suggest either using static IP configuration (NO DHCP) or doing some
work on the DHCP server - typically a router these days. Its quite hard
to have a *partial* DHCP configuration.

Your router may support different LAN address with different DHCP
configurations, to disable default route and DNS instances.
--
"Socialist governments traditionally do make a financial mess. They
always run out of other people's money. It's quite a characteristic of them"

Margaret Thatcher

On 26/04/2023 08:20, R.Wieser wrote:
>
> A new question though (if you don't mind) : I've been trying to disable ipv6
> too, and reading the man page for dhcpcd.conf I saw that I could use
> "ipv4only".
>

Try:
noipv6rs
noipv6

According to the BSD DHCPCD man page:

noipv6 Don't solicit or accept IPv6 Router Advertisements and DHCPv6.
noipv6rs Don't solicit or accept IPv6 Router Advertisements.

This seems to say that noipv6 includes noipv6rs, but Archwiki says
putting in both (in that order) works.

Have you looked at man dhcpcd.conf?

Arch wiki is a valuable resource e.g.
https://wiki.archlinux.org/title/dhcpcd
and usually better than alternatives.

--
Chris Elvidge
England

On 26/04/2023 08:20, R.Wieser wrote:
>
> In short : do you know of any source of info (website) which explains the
> network configuration, focussed on what is currently used by bullseye ?
>
Don't get too hung up on the raspbian/bullseye focus.
dhcpcd configuration is dhcpcd configuration no matter which distro
you're using.
Even the systemd invocation used by debian and thus raspbian is just a
straight invocation of dhcpcd.
As previous, try the archwiki.

--
Chris Elvidge
England

On 26/04/2023 13:07, Chris Elvidge wrote:
> On 26/04/2023 08:20, R.Wieser wrote:
>>
>> In short : do you know of any source of info (website) which explains the
>> network configuration, focussed on what is currently used by bullseye ?
>>
> Don't get too hung up on the raspbian/bullseye focus.
> dhcpcd configuration is dhcpcd configuration no matter which distro
> you're using.
> Even the systemd invocation used by debian and thus raspbian is just a
> straight invocation of dhcpcd.
> As previous, try the archwiki.
>
I thought the OP was trying to set up a DHCP client, not a server?

--
You can get much farther with a kind word and a gun than you can with a
kind word alone.

Al Capone

On Wed, 26 Apr 2023 09:20:30 +0200
"R.Wieser" <address@is.invalid> wrote:

> A new question though (if you don't mind) : I've been trying to disable
> ipv6 too, and reading the man page for dhcpcd.conf I saw that I could use
> "ipv4only".
>
> I've put that just above the "interface eth1" line (assuming that it
> would than work for all interfaces), but "ifconfig" still shows ipv6
> adresses for both "eth1" as well as "lo" (eth0 is disconnected).

What sort of ipv6 addresses ? If it is only link local ipv6
addresses (starting fe80::) then they don't come from DHCPCD but from IPv6
neighbour discovery and are probably quite hard to get rid of but they're
only valid on a LAN segment so I wouldn't worry about them too much.

--
Steve O'Hara-Smith
Odds and Ends at http://www.sohara.org/

On 26/04/2023 13:20, The Natural Philosopher wrote:
> On 26/04/2023 13:07, Chris Elvidge wrote:
>> On 26/04/2023 08:20, R.Wieser wrote:
>>>
>>> In short : do you know of any source of info (website) which explains
>>> the
>>> network configuration, focussed on what is currently used by bullseye ?
>>>
>> Don't get too hung up on the raspbian/bullseye focus.
>> dhcpcd configuration is dhcpcd configuration no matter which distro
>> you're using.
>> Even the systemd invocation used by debian and thus raspbian is just a
>> straight invocation of dhcpcd.
>> As previous, try the archwiki.
>>
> I thought the OP was trying to set up a DHCP client, not a server?
>

dhcpcd is client, isn't it?

--
Chris Elvidge
England

On 26/04/2023 14:21, Chris Elvidge wrote:
> On 26/04/2023 13:20, The Natural Philosopher wrote:
>> On 26/04/2023 13:07, Chris Elvidge wrote:
>>> On 26/04/2023 08:20, R.Wieser wrote:
>>>>
>>>> In short : do you know of any source of info (website) which
>>>> explains the
>>>> network configuration, focussed on what is currently used by bullseye ?
>>>>
>>> Don't get too hung up on the raspbian/bullseye focus.
>>> dhcpcd configuration is dhcpcd configuration no matter which distro
>>> you're using.
>>> Even the systemd invocation used by debian and thus raspbian is just
>>> a straight invocation of dhcpcd.
>>> As previous, try the archwiki.
>>>
>> I thought the OP was trying to set up a DHCP client, not a server?
>>
>
> dhcpcd is client, isn't it?
>
Thought it was the server

dhclient is the client. But I think there are many clients now. What
with systemd and network manager its all a muddle.

--
"In our post-modern world, climate science is not powerful because it is
true: it is true because it is powerful."

Lucas Bergkamp

On 26/04/2023 14:30, The Natural Philosopher wrote:
> On 26/04/2023 14:21, Chris Elvidge wrote:
>> On 26/04/2023 13:20, The Natural Philosopher wrote:
>>> On 26/04/2023 13:07, Chris Elvidge wrote:
>>>> On 26/04/2023 08:20, R.Wieser wrote:
>>>>>
>>>>> In short : do you know of any source of info (website) which
>>>>> explains the
>>>>> network configuration, focussed on what is currently used by
>>>>> bullseye ?
>>>>>
>>>> Don't get too hung up on the raspbian/bullseye focus.
>>>> dhcpcd configuration is dhcpcd configuration no matter which distro
>>>> you're using.
>>>> Even the systemd invocation used by debian and thus raspbian is just
>>>> a straight invocation of dhcpcd.
>>>> As previous, try the archwiki.
>>>>
>>> I thought the OP was trying to set up a DHCP client, not a server?
>>>
>>
>> dhcpcd is client, isn't it?
>>
> Thought it was the server
>
> dhclient is the client. But I think there are many clients now. What
> with systemd and network manager its all a muddle.
>
>

No. See previous. dhcpcd and dhclient are *different* dhcp clients.
dhclient is supplied by the ISC. dhclient is not normally used by
debian, slackware (or any other distros I use). They all use dhcpcd.
Even the systemd implementation used in debian uses dhcpcd. See
/usr/lib/systemd/system/dhcpcd.service
https://www.isc.org/blogs/dhcp-client-relay-eom/ says "ISC plans to end
maintenance of the ISC DHCP client and relay by the end of Q1, 2022."
Hence dhclient is end-of-life (IMHO).
I don't know about NetworkManager (or nmcli), I don't use it. A quick
look on Archwiki and /usr/lib/systemd/system/NetworkManager.service says
it is dbus based.

--
Chris Elvidge
England

On 26/04/2023 13:36, Ahem A Rivet's Shot wrote:
> On Wed, 26 Apr 2023 09:20:30 +0200
> "R.Wieser" <address@is.invalid> wrote:
>
>> A new question though (if you don't mind) : I've been trying to disable
>> ipv6 too, and reading the man page for dhcpcd.conf I saw that I could use
>> "ipv4only".
>>
>> I've put that just above the "interface eth1" line (assuming that it
>> would than work for all interfaces), but "ifconfig" still shows ipv6
>> adresses for both "eth1" as well as "lo" (eth0 is disconnected).
>
> What sort of ipv6 addresses ? If it is only link local ipv6
> addresses (starting fe80::) then they don't come from DHCPCD but from IPv6
> neighbour discovery and are probably quite hard to get rid of but they're
> only valid on a LAN segment so I wouldn't worry about them too much.
>

It seems there are 2 ways to totally disable ipv6
https://www.howtoraspberry.com/2020/04/disable-ipv6-on-raspberry-pi/

1) Pi only: add 'ipv6.disable=1' to end of line in /boot/cmdline.txt

2) Generally,
a) if using sysctl: put a file in /etc/sysctl.d/ containing
net.ipv6.conf.all.disable_ipv6 = 1
net.ipv6.conf.default.disable_ipv6 = 1
net.ipv6.conf.lo.disable_ipv6 = 1
b) if not using sysctl, add
echo 1 > /proc/sys/net/ipv6/conf/all/disable_ipv6
echo 1 > /proc/sys/net/ipv6/conf/default/disable_ipv6
echo 1 > /proc/sys/net/ipv6/conf/lo/disable_ipv6
to end of (for e.g.) /etc/rc.local

Both methods will disable all ipv6 including link-local
NetworkManager has a "disable" option under ipV6, too.

--
Chris Elvidge
England

On 26/04/2023 14:45, Chris Elvidge wrote:

> No. See previous. dhcpcd and dhclient are *different* dhcp clients.
> dhclient is supplied by the ISC. dhclient is not normally used by
> debian, slackware (or any other distros I use). They all use dhcpcd.
> Even the systemd implementation used in debian uses dhcpcd. See
> /usr/lib/systemd/system/dhcpcd.service
> https://www.isc.org/blogs/dhcp-client-relay-eom/ says "ISC plans to end
> maintenance of the ISC DHCP client and relay by the end of Q1, 2022."
> Hence dhclient is end-of-life (IMHO).
> I don't know about NetworkManager (or nmcli), I don't use it. A quick
> look on Archwiki and /usr/lib/systemd/system/NetworkManager.service says
> it is dbus based.
>
Ubuntu is still using dhclient, isn't it?

On 26/04/2023 17:22, Pancho wrote:
> On 26/04/2023 14:45, Chris Elvidge wrote:
>
>> No. See previous. dhcpcd and dhclient are *different* dhcp clients.
>> dhclient is supplied by the ISC. dhclient is not normally used by
>> debian, slackware (or any other distros I use). They all use dhcpcd.
>> Even the systemd implementation used in debian uses dhcpcd. See
>> /usr/lib/systemd/system/dhcpcd.service
>> https://www.isc.org/blogs/dhcp-client-relay-eom/ says "ISC plans to
>> end maintenance of the ISC DHCP client and relay by the end of Q1,
>> 2022." Hence dhclient is end-of-life (IMHO).
>> I don't know about NetworkManager (or nmcli), I don't use it. A quick
>> look on Archwiki and /usr/lib/systemd/system/NetworkManager.service
>> says it is dbus based.
>>
> Ubuntu is still using dhclient, isn't it?

No idea.
Does `ps ax | grep dhc` give a clue?
Does nmcli work? -> uses NetworkManager

--
Chris Elvidge
England

On 26/04/2023 17:57, Chris Elvidge wrote:
> On 26/04/2023 17:22, Pancho wrote:
>> On 26/04/2023 14:45, Chris Elvidge wrote:
>>
>>> No. See previous. dhcpcd and dhclient are *different* dhcp clients.
>>> dhclient is supplied by the ISC. dhclient is not normally used by
>>> debian, slackware (or any other distros I use). They all use dhcpcd.
>>> Even the systemd implementation used in debian uses dhcpcd. See
>>> /usr/lib/systemd/system/dhcpcd.service
>>> https://www.isc.org/blogs/dhcp-client-relay-eom/ says "ISC plans to
>>> end maintenance of the ISC DHCP client and relay by the end of Q1,
>>> 2022." Hence dhclient is end-of-life (IMHO).
>>> I don't know about NetworkManager (or nmcli), I don't use it. A quick
>>> look on Archwiki and /usr/lib/systemd/system/NetworkManager.service
>>> says it is dbus based.
>>>
>> Ubuntu is still using dhclient, isn't it?
>
> No idea.
> Does `ps ax | grep dhc` give a clue?
> Does nmcli work? -> uses NetworkManager
>

Seems my Ubuntu 22.04 systems only get nmcli with the
ubuntu-gnome-desktop package. My server versions don't have it. Both
server and desktop still have dhclient.

Do I need to learn nmcli, or can I bury my head in the sand and hope it
goes away?

On 26/04/2023 17:57, Chris Elvidge wrote:
> On 26/04/2023 17:22, Pancho wrote:
>> On 26/04/2023 14:45, Chris Elvidge wrote:
>>
>>> No. See previous. dhcpcd and dhclient are *different* dhcp clients.
>>> dhclient is supplied by the ISC. dhclient is not normally used by
>>> debian, slackware (or any other distros I use). They all use dhcpcd.
>>> Even the systemd implementation used in debian uses dhcpcd. See
>>> /usr/lib/systemd/system/dhcpcd.service
>>> https://www.isc.org/blogs/dhcp-client-relay-eom/ says "ISC plans to
>>> end maintenance of the ISC DHCP client and relay by the end of Q1,
>>> 2022." Hence dhclient is end-of-life (IMHO).
>>> I don't know about NetworkManager (or nmcli), I don't use it. A quick
>>> look on Archwiki and /usr/lib/systemd/system/NetworkManager.service
>>> says it is dbus based.
>>>
>> Ubuntu is still using dhclient, isn't it?
>
> No idea.
> Does `ps ax | grep dhc` give a clue?
> Does nmcli work? -> uses NetworkManager
>

My Mint uses neither. There is an nm-applet.
But dhcp is only used at boot time normally.

--
When plunder becomes a way of life for a group of men in a society, over
the course of time they create for themselves a legal system that
authorizes it and a moral code that glorifies it.

Frédéric Bastiat

On 26/04/2023 17:57, Chris Elvidge wrote:
> On 26/04/2023 17:22, Pancho wrote:
>> On 26/04/2023 14:45, Chris Elvidge wrote:
>>
>>> No. See previous. dhcpcd and dhclient are *different* dhcp clients.
>>> dhclient is supplied by the ISC. dhclient is not normally used by
>>> debian, slackware (or any other distros I use). They all use dhcpcd.
>>> Even the systemd implementation used in debian uses dhcpcd. See
>>> /usr/lib/systemd/system/dhcpcd.service
>>> https://www.isc.org/blogs/dhcp-client-relay-eom/ says "ISC plans to
>>> end maintenance of the ISC DHCP client and relay by the end of Q1,
>>> 2022." Hence dhclient is end-of-life (IMHO).
>>> I don't know about NetworkManager (or nmcli), I don't use it. A quick
>>> look on Archwiki and /usr/lib/systemd/system/NetworkManager.service
>>> says it is dbus based.
>>>
>> Ubuntu is still using dhclient, isn't it?
>
> No idea.
> Does `ps ax | grep dhc` give a clue?
> Does nmcli work? -> uses NetworkManager
>
Only think that looks relevant on my rig is 'NetworkManager

The config file seems to be

/etc/NetworkManager/system-connections/Wired connection 1.nmconnection
------>
[connection]
id=Wired connection 1
uuid=200b0367-8dfe-331b-b244-aa11e7de1cea
type=ethernet
autoconnect-priority=-999
interface-name=eno1
permissions=
timestamp=1674452619

[ethernet]
mac-address-blacklist=

[ipv4]
dns-search=
method=auto

[ipv6]
addr-gen-mode=stable-privacy
dns-search=
ip6-privacy=0
method=auto

[proxy]
<-------------

--
Karl Marx said religion is the opium of the people.
But Marxism is the crack cocaine.

On 2023-04-26, Chris Elvidge <chris@mshome.net> wrote:
> On 26/04/2023 13:36, Ahem A Rivet's Shot wrote:
>> On Wed, 26 Apr 2023 09:20:30 +0200
>> "R.Wieser" <address@is.invalid> wrote:
>>
>>> A new question though (if you don't mind) : I've been trying to disable
>>> ipv6 too, and reading the man page for dhcpcd.conf I saw that I could use
>>> "ipv4only".
>>>
>>> I've put that just above the "interface eth1" line (assuming that it
>>> would than work for all interfaces), but "ifconfig" still shows ipv6
>>> adresses for both "eth1" as well as "lo" (eth0 is disconnected).
>>
>> What sort of ipv6 addresses ? If it is only link local ipv6
>> addresses (starting fe80::) then they don't come from DHCPCD but from IPv6
>> neighbour discovery and are probably quite hard to get rid of but they're
>> only valid on a LAN segment so I wouldn't worry about them too much.
>>
>
> It seems there are 2 ways to totally disable ipv6
> https://www.howtoraspberry.com/2020/04/disable-ipv6-on-raspberry-pi/
>
> 1) Pi only: add 'ipv6.disable=1' to end of line in /boot/cmdline.txt

Just a small quibble - while the whole /boot/cmfline.txt thing is Pi
specific, the ipv6.disable=1 kernel parameter setting should work on all
Linux kernels.

> 2) Generally,
> a) if using sysctl: put a file in /etc/sysctl.d/ containing
> net.ipv6.conf.all.disable_ipv6 = 1
> net.ipv6.conf.default.disable_ipv6 = 1
> net.ipv6.conf.lo.disable_ipv6 = 1
> b) if not using sysctl, add
> echo 1 > /proc/sys/net/ipv6/conf/all/disable_ipv6
> echo 1 > /proc/sys/net/ipv6/conf/default/disable_ipv6
> echo 1 > /proc/sys/net/ipv6/conf/lo/disable_ipv6
> to end of (for e.g.) /etc/rc.local
>
> Both methods will disable all ipv6 including link-local
> NetworkManager has a "disable" option under ipV6, too.
>

On Wed, 26 Apr 2023 19:14:46 +0100
The Natural Philosopher <tnp@invalid.invalid> wrote:

> But dhcp is only used at boot time normally.

Either dhclient or dhcpcd should persist so that it can renew the
lease when the time comes - try a ps -elf | grep dhclient or pgrep -lf
dhclient.

--
Steve O'Hara-Smith
Odds and Ends at http://www.sohara.org/