samba - Mar 2021 - Domain member cannot authenticate when first domain controller is down

Further fiddling with this has shown something strange. If I enter my username
and password in an attempt to authenticate a domain user, it will take 60+
seconds for it to fail to log in. However, during said 60+ seconds, if I log in
via SSH as a non-domain user, then the domain user login succeeds. What could
cause that?


________________________________
From: Roy Eastwood <spindles7 at gmail.com>
Sent: Saturday, February 27, 2021 1:27 AM
To: 'Josh T' <c3h4ohcooh3 at hotmail.com>; samba at
lists.samba.org <samba at lists.samba.org>
Subject: Re: [Samba] Domain member cannot authenticate when first domain
controller is down



On 27 February 2021 03:35 Josh T wrote:
> //Problem:
> I am unable to authenticate a domain user on a Samba domain member while
the
> first Samba directory controller DC1 is powered off and the second Samba
> directory controller DC2 is powered on.
>
> While DC1 is powered on, I can log in as a domain user with no problems.
While
> DC1 is powered off, attempting to log in usually results in waiting 60+
seconds
> followed by a login failure message. If I had already logged in prior to
powering
> off DC1, then I can see the same long delay and authentication failures
when
> entering my sudo password. Intermittently I can sometimes manage to log in
> while DC1 is powered off, but there is still the 60+ second delay; I
haven't
been
> able to link this intermittent behavior to any of my own troubleshooting
actions.
> In any case, a 60+ second delay is undesirable.
>
> //Environment description:
> The first Samba domain controller DC1 was created following these
instructions
> on the Samba wiki:
> https://wiki.samba.org/index.php/Setting_up_Samba_as_an_Active_Directory_
> Domain_Controller
> It was provisioned using the command "samba-tool domain provision
--use-
> rfc2307 --interactive".
> The BIND9_DLZ DNS backend was selected during provisioning.
> Samba version 4.11.6-Ubuntu was installed on DC1 using the apt command.
>
> The second Samba domain controller DC2 was created following these
> instructions on the Samba wiki:
> https://wiki.samba.org/index.php/Joining_a_Samba_DC_to_an_Existing_Active
> _Directory
> It was joined using the command "samba-tool domain join my.domain.tld
--dns-
> backend=BIND9_DLZ --option='idmap_ldb:use rfc2307 = yes'".
The above is missing the letters  "DC" in the command line.   This may
be the
issue.

HTH

Roy

Josh, I don't have the answer to your question, but if you ever figure 
it out, I would like to know the answer, too.

The 2nd DC that I built has been of very little use.? While building, it 
passed all the tests in the wiki.? After building, I found some DNS 
entries that were not created during the join. Rowland kindly helped me 
add and/or edit the affected entries, and I hoped for better results.? 
However, it was not to be.? If the 1st DC is removed from the network, 
any kind of login or getent is interminably long or times out.? So, 
while I easily see the theoretical value of having multiple DC's, I'm 
having trouble seeing the actual, practical benefit of having them.? 
There is no instant failover, and often times, there is complete failure 
of necessary AD functions.? While it's certainly possible the problem 
could be me, I cannot troubleshoot what the problem is.

Dale


On 3/1/21 6:25 PM, Josh T via samba wrote:
> Further fiddling with this has shown something strange. If I enter my
username and password in an attempt to authenticate a domain user, it will take
60+ seconds for it to fail to log in. However, during said 60+ seconds, if I log
in via SSH as a non-domain user, then the domain user login succeeds. What could
cause that?
>
>
> ________________________________
> From: Roy Eastwood <spindles7 at gmail.com>
> Sent: Saturday, February 27, 2021 1:27 AM
> To: 'Josh T' <c3h4ohcooh3 at hotmail.com>; samba at
lists.samba.org <samba at lists.samba.org>
> Subject: Re: [Samba] Domain member cannot authenticate when first domain
controller is down
>
>
>
> On 27 February 2021 03:35 Josh T wrote:
>> //Problem:
>> I am unable to authenticate a domain user on a Samba domain member
while the
>> first Samba directory controller DC1 is powered off and the second
Samba
>> directory controller DC2 is powered on.
>>
>> While DC1 is powered on, I can log in as a domain user with no
problems. While
>> DC1 is powered off, attempting to log in usually results in waiting 60+
> seconds
>> followed by a login failure message. If I had already logged in prior
to
> powering
>> off DC1, then I can see the same long delay and authentication failures
when
>> entering my sudo password. Intermittently I can sometimes manage to log
in
>> while DC1 is powered off, but there is still the 60+ second delay; I
haven't
> been
>> able to link this intermittent behavior to any of my own
troubleshooting
> actions.
>> In any case, a 60+ second delay is undesirable.
>>
>> //Environment description:
>> The first Samba domain controller DC1 was created following these
instructions
>> on the Samba wiki:
>>
https://wiki.samba.org/index.php/Setting_up_Samba_as_an_Active_Directory_
>> Domain_Controller
>> It was provisioned using the command "samba-tool domain provision
--use-
>> rfc2307 --interactive".
>> The BIND9_DLZ DNS backend was selected during provisioning.
>> Samba version 4.11.6-Ubuntu was installed on DC1 using the apt command.
>>
>> The second Samba domain controller DC2 was created following these
>> instructions on the Samba wiki:
>>
https://wiki.samba.org/index.php/Joining_a_Samba_DC_to_an_Existing_Active
>> _Directory
>> It was joined using the command "samba-tool domain join
my.domain.tld --dns-
>> backend=BIND9_DLZ --option='idmap_ldb:use rfc2307 = yes'".
> The above is missing the letters  "DC" in the command line.  
This may be the
> issue.
>
> HTH
>
> Roy
>
>
>
>

Check the following. 

dig ns $(hostname -d)
You should see all the AD-DC servers, if not add the NS record of the missing
ones, then when thats done.

try these settings and test what works best for you, add in /etc/resolv.conf

options timeout:3
options attempts:2
options rotate

(see : man resolv.conf what these do) 

in smb.conf.. 
Try setting : 

cache directory = /var/cache/samba
(do check if the folder exists. )

these parts would be the first one's i would look into. 

I hope this can help you. 

Greetz, 

Louis

> -----Oorspronkelijk bericht-----
> Van: samba [mailto:samba-bounces at lists.samba.org] Namens Dale via samba
> Verzonden: woensdag 3 maart 2021 16:25
> Aan: Josh T; Roy Eastwood; samba at lists.samba.org
> Onderwerp: Re: [Samba] Domain member cannot authenticate when first domain
> controller is down
> 
> Josh, I don't have the answer to your question, but if you ever figure
> it out, I would like to know the answer, too.
> 
> The 2nd DC that I built has been of very little use.? While building, it
> passed all the tests in the wiki.? After building, I found some DNS
> entries that were not created during the join. Rowland kindly helped me
> add and/or edit the affected entries, and I hoped for better results.
> However, it was not to be.? If the 1st DC is removed from the network,
> any kind of login or getent is interminably long or times out.? So,
> while I easily see the theoretical value of having multiple DC's,
I'm
> having trouble seeing the actual, practical benefit of having them.
> There is no instant failover, and often times, there is complete failure
> of necessary AD functions.? While it's certainly possible the problem
> could be me, I cannot troubleshoot what the problem is.
> 
> Dale
> 
> 
> On 3/1/21 6:25 PM, Josh T via samba wrote:
> > Further fiddling with this has shown something strange. If I enter my
> username and password in an attempt to authenticate a domain user, it will
> take 60+ seconds for it to fail to log in. However, during said 60+
> seconds, if I log in via SSH as a non-domain user, then the domain user
> login succeeds. What could cause that?
> >
> >
> > ________________________________
> > From: Roy Eastwood <spindles7 at gmail.com>
> > Sent: Saturday, February 27, 2021 1:27 AM
> > To: 'Josh T' <c3h4ohcooh3 at hotmail.com>; samba at
lists.samba.org
> <samba at lists.samba.org>
> > Subject: Re: [Samba] Domain member cannot authenticate when first
domain
> controller is down
> >
> >
> >
> > On 27 February 2021 03:35 Josh T wrote:
> >> //Problem:
> >> I am unable to authenticate a domain user on a Samba domain member
> while the
> >> first Samba directory controller DC1 is powered off and the second
> Samba
> >> directory controller DC2 is powered on.
> >>
> >> While DC1 is powered on, I can log in as a domain user with no
> problems. While
> >> DC1 is powered off, attempting to log in usually results in
waiting 60+
> > seconds
> >> followed by a login failure message. If I had already logged in
prior
> to
> > powering
> >> off DC1, then I can see the same long delay and authentication
failures
> when
> >> entering my sudo password. Intermittently I can sometimes manage
to log
> in
> >> while DC1 is powered off, but there is still the 60+ second delay;
I
> haven't
> > been
> >> able to link this intermittent behavior to any of my own
> troubleshooting
> > actions.
> >> In any case, a 60+ second delay is undesirable.
> >>
> >> //Environment description:
> >> The first Samba domain controller DC1 was created following these
> instructions
> >> on the Samba wiki:
> >>
> https://wiki.samba.org/index.php/Setting_up_Samba_as_an_Active_Directory_
> >> Domain_Controller
> >> It was provisioned using the command "samba-tool domain
provision --
> use-
> >> rfc2307 --interactive".
> >> The BIND9_DLZ DNS backend was selected during provisioning.
> >> Samba version 4.11.6-Ubuntu was installed on DC1 using the apt
command.
> >>
> >> The second Samba domain controller DC2 was created following these
> >> instructions on the Samba wiki:
> >>
> https://wiki.samba.org/index.php/Joining_a_Samba_DC_to_an_Existing_Active
> >> _Directory
> >> It was joined using the command "samba-tool domain join
my.domain.tld -
> -dns-
> >> backend=BIND9_DLZ --option='idmap_ldb:use rfc2307 =
yes'".
> > The above is missing the letters  "DC" in the command line. 
This may
> be the
> > issue.
> >
> > HTH
> >
> > Roy
> >
> >
> >
> >
> 
> 
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