Re: 15-STABLE: dhclient fails on em0 (Lenovo T580)

Am Tage des Herren Thu, 4 Dec 2025 11:51:35 +0100 (CET)
Ronald Klop <ronald-lists@klop.ws> schrieb:

Hello,

> Hi,
> 
> You have dhcp6c configured on a lagg0 interface, and the lagg0 interface is created, but not
> configured anywhere in your configuration. But your problem is about IPv4 and not IPv6. So
> it might not be related. But it makes me wonder about your config.

that shouldn't have any impact on IPv4 on em0 and/or wlan0.

lagg0 is unused and a remnant from a prior used configuration aggregating em0 and wlan0 using
alternatively LAN and WiFi. This worked with if_iwm, but diesn't with if_iwlwifi - or
doesn't work with 15 at all. It is unuse, but present ... 

> 
> I can't find in your log messages that dhclient is ever started.

Me neither. But setting SYNCDHCP with the desired NIC solves - for now - the problem.
Alternatively, setting 'synchronous_dhclient="YES" ' does the same.

On the console, I see a lot of UP and DOWN of the NIC (especially em0 with my home switch), I
see this with several switches at work, too, but there are other switches which do not flap
like hell. Maybe this is something worth to note herein. Some switches may have some issues
with negotiating the correct uplink speed, but at that point I can not fathom why also OpenWRT
based APs show the very same symptomes sometimes. Maybe this observation shows some deeper
issues ...

> Can you try to configure ifconfig_em0="SYNCDHCP" instead of "DHCP"? That should start
> dhclient earlier and wait for the IP and must give output of dhclient. Please reply with the
> console log output of that boot run.
> 
> To me your configuration looks really messy, so I'm sorry that I can't really help you any
> further. I can't easily figure out what you configured and what is still the default. My
> advice would be to remove all the defaults from your /etc/rc.conf and only keep lines that
> actually configure something.

Well, apity, but my rc.conf is a straight forward copy of defaults/rc.conf with changes
according to my necessities at the bureau/lab. I can not memorize all tags withing rc.conf, so
having them in straight and plain sight is sometimes very convenient to adapt to new
situations. I do not know how you folks proceed in such situations, any idea making life
easier is welcome.

As mentioned prior in this thread, I do a regular "sdiff " even when changing
minor versions.

> 
> I hope you figure out the issue some day.

Thank you very much, your help was/is much appreciated! 

> 
> Regards,
> Ronald.

Kind regards,

oh
> 
> 
>  
> Van: A FreeBSD User <freebsd@walstatt-de.de>
> Datum: woensdag, 3 december 2025 11:34
> Aan: Ronald Klop <ronald-lists@klop.ws>
> CC: FreeBSD CURRENT <freebsd-current@freebsd.org>, "Dag-Erling Smørgrav" <des@FreeBSD.org>
> Onderwerp: Re: 15-STABLE: dhclient fails on em0 (Lenovo T580)
> > 
> > Am Tage des Herren Wed, 3 Dec 2025 11:17:50 +0100 (CET)
> > Ronald Klop <ronald-lists@klop.ws> schrieb:
> >   
> > > Hi,
> > >
> > > Did you copy /etc/defaults/rc.conf to /etc/rc.conf?  
> > 
> > Yes, I do, since I change things on an experimental basis quite often.
> > 
> > That never induced any issue in the last decades using this kind of approach. Each variable
> > set in defaults/rc.conf should be cleanly overriden via rc.conf and rc.conf.local,
> > shouldn't it? The only possible issue I could imagine is the order variables appear and
> > being processed by rc.subr and siblings ... or am I wrong?
> > 
> > Kind regards,
> > oh  
> > >
> > > AFAIK, the idea is to only override settings from /etc/defaults/rc.conf in /etc/rc.conf.
> > > My rc.conf is usually just 10 or 20 lines. Some network config and enabling some
> > > services. Like what you have in /etc/rc.conf.local.
> > >
> > > Regards,
> > > Ronald.
> > >
> > >  
> > > Van: FreeBSD User <freebsd@walstatt-de.de>
> > > Datum: woensdag, 3 december 2025 10:15
> > > Aan: "Dag-Erling Smørgrav" <des@FreeBSD.org>
> > > CC: FreeBSD CURRENT <freebsd-current@freebsd.org>
> > > Onderwerp: Re: 15-STABLE: dhclient fails on em0 (Lenovo T580)  
> > > >
> > > > On Tue, 02 Dec 2025 20:51:33 +0100
> > > > Dag-Erling Smørgrav <des@FreeBSD.org> wrote:
> > > >     
> > > > > A FreeBSD User <freebsd@walstatt-de.de> writes:    
> > > > > > Dag-Erling Smørgrav <des@FreeBSD.org> writes:      
> > > > > > > As a workaround, add this to /boot/loader.conf:
> > > > > > >
> > > > > > >     net.inet.ip.fw.default_to_accept="1"      
> > > > > > the above "trick" doesn't help.      
> > > > >
> > > > > This is concerning.
> > > > >
> > > > > The fact that `dhclient em0` works after the firewall is up proves that
> > > > > the firewall rules themselves are not the issue.  I therefore assumed
> > > > > that the problem was that dhclient was trying to acquire a lease before
> > > > > the firewall was configured.  Switching default_to_accept on should have
> > > > > made that possible.  The fact that it doesn't means the firewall isn't
> > > > > to blame at all.  Something else is causing dhclient not to run at boot.
> > > > >
> > > > > Could you please provide the output from the following command:
> > > > >
> > > > >     grep -r '^[^#]' /etc/rc.conf*
> > > > >
> > > > > Could you please also provide a log of the boot messages, if possible?
> > > > >
> > > > > DES    
> > > >
> > > > Having had a feeling that statically compiling in FIREWALL (ipw) support into
> > > > my kernel, I tested by excluding the appropritae lines and adding the
> > > > /boot/loader.conf.local line again allow packets by default. Result is the very
> > > > same.
> > > >
> > > > Attached you'll find the requested files.
> > > >
> > > > A side note: I do etcupdate on a regular basis on all of the maintained boxes.
> > > >
> > > > Kind regards,
> > > >
> > > > oh
> > > >
> > > >
> > > >
> > > >      
> > >
> > >    
> > 
> > 
> > 
> > -- 
> > 
> > A FreeBSD user
> > 
> > 
> > 
> >    
> 
>  



-- 

A FreeBSD user