[Samba] DNS problems in my domain

[3ddFreak via samba]

The users in our network are experiencing some dns problems.
When i take closer look to our samba configuration I see that we have a corrupted ldb file (/var/lib/samba/private/sam.ldb.d/DC=DOMAINDNSZONES,DC=********,DC=COM.ldb).
I can still access the DNS entries from the Microsoft remote server administration tools.

What are my best options?
I have a backup of the ldb files from 2 months ago(no dns entries changed since), should i try to replace the ldb file with the older one? Why not?
Can i safely delete the ldb and will a reboot of samba recreate the file?
Should I start over? Create a new Domain Controller?

Can anyone explain the purpose of this file? Is it only responsible for the internal DNS?

Error in Syslog:
ldb: ltdb: tdb(/var/lib/samba/private/sam.ldb.d/DC=DOMAINDNSZONES,DC=********,DC=COM.ldb): tdb_rec_read bad magic 0x444e4940 at offset=88929584

Ubuntu 14.04 LTS
Samba version: 4.1.6

Thx in advance

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[Rowland Penny via samba]

On Wed, 8 Feb 2017 13:32:36 +0100 (CET)
3ddFreak via samba <sa...@lists.samba.org> wrote:

> The users in our network are experiencing some dns problems.
> When i take closer look to our samba configuration I see that we have
> a corrupted ldb file
> (/var/lib/samba/private/sam.ldb.d/DC=DOMAINDNSZONES,DC=********,DC=COM.ldb).
> I can still access the DNS entries from the Microsoft remote server
> administration tools.
>
> What are my best options?
> I have a backup of the ldb files from 2 months ago(no dns entries
> changed since), should i try to replace the ldb file with the older
> one?

NO, definitely not

> Why not?
Because other things will have changed and you will break your AD

> Can i safely delete the ldb and will a reboot of samba
> recreate the file?

If you delete the file, it will not be recreated.

> Should I start over? Create a new Domain
> Controller?

Try running 'samba-tool dbcheck --cross-ncs --fix --yes'

If that doesn't work, upgrade Samba if you can, later versions have
better repair tools. Starting with a new AD should be the last resort.

>
> Can anyone explain the purpose of this file? Is it only responsible
> for the internal DNS?

It is where the domain dns records are stored, you shouldn't really try
to alter anything in the files in sam.ldb.d, only change 'sam.ldb'.

>
> Error in Syslog:
> ldb: ltdb:
> tdb(/var/lib/samba/private/sam.ldb.d/DC=DOMAINDNSZONES,DC=********,DC=COM.ldb):
> tdb_rec_read bad magic 0x444e4940 at offset=88929584
>
> Ubuntu 14.04 LTS
> Samba version: 4.1.6

The 4.1.x versions are now EOL as far as Samba is concerned.

Rowland

[Rowland Penny via samba]

On Wed, 8 Feb 2017 15:06:28 +0100 (CET)
3ddFreak <alex...@verbeke.com> wrote:

> Thx for the quick reply.
>
> Repairing the ldb file with 'samba-tool dbcheck --cross-ncs --fix
> --yes' failed.
>
> I'm afraid that upgrading my Samba will definitely break my AD.
> (because the corrupt file)

Upgrading shouldn't touch the .ldb files, it should only replace the
binaries etc.

>
> What is the best method to migrate my AD to another newer Samba DC?

You could try adding another DC, but this may not work because of
your .ldb files.

Rowland