samba - Sep 2024 - Netbios Issue

Hello,

I have been running Samba for many many years and have have not had this 
issue, so I hope someone can point me in the right direction.

I am currently running in production Samba 4.7.7 on RHEL 7.9.? It has 
been running without issue until yesterday.? I am building a new server 
to replace the one currently running Samba, this time with RHEL 8.10 and 
Samba 4.21.0.

On the RH8 machine I downloaded and built from source 4.21.0.? I copied 
the smb.conf file from my current production server over to the new 
server.? I did not change the netbios name as I just assumed (how 
foolish of me) that I would see two Samba servers with the same name.? I 
then ran these two commands:

kinit admin_user at my.domain (I entered my password and got a ticket)
net ads join -U admin_user

When I did this, my production server stopped accepting requests to 
mount shares by the netbios name.? A little more info, in DNS my name 
will be "foo-bar.my.domain" also in DNS is an alias
"foobar.my.domain"
that points back to "foo-bar".? I immediately shutdown the new server 
with 4.21.0.? I then went to my Windows DC and removed the foo-bar name, 
and then re-added the 4.7.7 server back to the domain controller.? It 
added without issue.? But I still can not mount shares via \\foo-bar\share.

I can mount shares using the alias \\foobar\share or the IP address of 
the machine or even \\foo-bar.my.domain\share.? The \\foo-bar\ name 
seems to be cached somewhere and I just can not figure out where it is 
so I can remove it.

Am I making sense?? Sorry for the wall of text.

Thank you for any help you can provide.

mike

On Sat, 14 Sep 2024 10:41:40 -0400
Mike Hobbs via samba <samba at lists.samba.org> wrote:
> Hello,
> 
> I have been running Samba for many many years and have have not had
> this issue, so I hope someone can point me in the right direction.
> 
> I am currently running in production Samba 4.7.7 on RHEL 7.9.? It has 
> been running without issue until yesterday.? I am building a new
> server to replace the one currently running Samba, this time with
> RHEL 8.10 and Samba 4.21.0.
> 
> On the RH8 machine I downloaded and built from source 4.21.0.
I do hope you used the built in Heimdal.
>? I
> copied the smb.conf file from my current production server over to
> the new server.? I did not change the netbios name as I just assumed
> (how foolish of me) that I would see two Samba servers with the same
> name.
The netbios name on a Unix domain member must be the same as the short
hostname, would you have two machines with the same hostname ?
>? I then ran these two commands:
> 
> kinit admin_user at my.domain (I entered my password and got a ticket)
> net ads join -U admin_user
> 
> When I did this, my production server stopped accepting requests to 
> mount shares by the netbios name.? A little more info, in DNS my name 
> will be "foo-bar.my.domain" also in DNS is an alias
> "foobar.my.domain" that points back to "foo-bar".
Don't you mean 'CNAME' instead of 'alias' ?
>? I immediately
> shutdown the new server with 4.21.0.? I then went to my Windows DC
> and removed the foo-bar name, and then re-added the 4.7.7 server back
> to the domain controller.? It added without issue.? But I still can
> not mount shares via \\foo-bar\share.
> 
> I can mount shares using the alias \\foobar\share or the IP address
> of the machine or even \\foo-bar.my.domain\share.? The \\foo-bar\
> name seems to be cached somewhere and I just can not figure out where
> it is so I can remove it.
> 
Are you sure that the 'join' didn't replace the computers info in AD
?

Can we please see the output of 'testparm -s'

Samba 4.7.x didn't require winbind, but from 4.8.0 you must run
winbind, so, are you running it ?

Rowland