samba - Jul 2025 - WERR_DNS_ERROR_DS_UNAVAILABLE when asking for local dns server info

On Thu, 3 Jul 2025 08:59:35 +0200
"CED Ing. Damiano Bolla via samba" <samba at lists.samba.org>
wrote:
> this is what works
> 
> ----------------------
> 
> root at vdce:/home/damiano/work# cat /etc/hostname
> vdce
> 
> ----------------------
> 
> root at vdce:/home/damiano/work# cat /etc/hosts
> 127.0.0.1?????? localhost
> 192.168.999.40? vdce.CONTOSO.local???? vdce
> 
> ----------------------
> 
> root at vdce:/home/damiano/work# cat /etc/krb5.conf
> [libdefaults]
>  ??????? default_realm = CONTOSO.LOCAL
>  ??????? dns_lookup_realm = false
>  ??????? dns_lookup_kdc = true
> 
> [realms]
> CONTOSO.LOCAL = {
>  ??????? default_domain = CONTOSO.local
> }
> 
> [domain_realm]
>  ??????? VDCE = CONTOSO.LOCAL
> 
> ----------------------
> 
> root at vdce:/home/damiano/work# cat /etc/nsswitch.conf
> # /etc/nsswitch.conf
> #
> # Example configuration of GNU Name Service Switch functionality.
> # If you have the `glibc-doc-reference' and `info' packages
> installed, try: # `info libc "Name Service Switch"' for
information
> about this file.
> 
> passwd:???????? files
> group:????????? files
> shadow:???????? files
> gshadow:??????? files
> 
> #hosts:????????? files mdns4_minimal [NOTFOUND=return] dns
> hosts:????????? files dns
> networks:?????? files
> 
> protocols:????? db files
> services:?????? db files
> ethers:???????? db files
> rpc:??????????? db files
> 
> netgroup:?????? nis
> 
> ----------------------
> 
> root at vdce:/home/damiano/work# nslookup vdce
> Server:???????? 192.168.999.40
> Address:??????? 192.168.999.40#53
> 
> Name:?? vdce.CONTOSO.local
> Address: 192.168.999.40
> 
> ----------------------
> 
> root at vdce:/home/damiano/work#? net --use-krb5-ccache=/tmp/krb5cc_0 -S 
> virtdc time
> Thu Jul? 3 08:50:12 2025
> 
> ----------------------
> 
> root at vdce:/home/damiano/work#? net --use-krb5-ccache=/tmp/krb5cc_0 -S 
> vdce time
> Thu Jul? 3 08:49:31 2025
> ----------------------
> 
> I can use RSAT (from windows machine, clearly) to connect to xx.40
> and administer "active directory users and computers"
> 
> ---------------------- I have removed the other windows machines from 
> the report
> 
> PS C:\Users\xxxxxxx> repadmin /replsummary
> Replication Summary Start Time: 2025-07-03 08:56:54
> 
> Source DSA????????? largest delta??? fails/total %%?? error
>  ?VDCD????????????????????? 03m:58s??? 0 /? 10??? 0
> 
> Destination DSA???? largest delta??? fails/total %%?? error
>  ?VDCD????????????????????? 59m:57s??? 0 /? 10??? 0
> 
> 
Well, everything looks ok, but I missed asking for /etc/resolv.conf,
from what you have posted, it should look like this:

search contoso.local
nameserver 192.168.999.40

If it doesn't, then I suggest you edit it to match and try again.
> ---------------------------------- however....
> 
> root at vdce:/home/damiano/work# samba-tool dns serverinfo vdce 
> --use-krb5-ccache=/tmp/krb5cc_0
> ERROR(runtime): Could not contact RPC server 
> [WERR_DNS_ERROR_DS_UNAVAILABLE] - (9717,
> 'WERR_DNS_ERROR_DS_UNAVAILABLE')
> 
> the question, again....
> 
> the question is "how can I find out if RPC server for DNS (that is
> NOT the dns server itself, it is the "administrative" part) is
> "enabled") ?
Does running the following command on the DC produce output ?:
ps ax | grep 'samba' | grep 'rpc'

You could try the rpcclient command:

rpcclient  -U "" -N -I 192.168.999.40 -c srvinfo vdce

Does that produce output ?
> 
> and if it is not enabled.... how do I enable it ?
Thing is, it should be enabled, there is a default line in smb.conf on
a DC:

server services = s3fs, rpc, wrepl, ldap, cldap, kdc, drepl, winbindd,
ntp_signd, kcc, dnsupdate, dns

That is a list of the services that run on a DC and you have to remove
the service from the list (either by entering the line in your smb.conf
without the service(s) you want to stop or by entering "server services
-'the_service_you_do_not_want_to_run' e.g. 'server services
-dns')

While writing this, I remembered something from the beginning of the
year, so searched the mailing list archive, I wonder if this is your
problem ? :

https://lists.samba.org/archive/samba/2025-January/250736.html

Rowland

root at vdce:/home/damiano/work# ps ax | grep 'samba' | grep
'rpc'
 ?4580 ???????? S????? 0:00 samba: task[rpc] pre-fork master
 ?4586 ???????? S????? 1:35 samba: task[rpc] pre-forked worker(0)
 ?4590 ???????? S????? 0:00 samba: task[rpc] pre-forked worker(1)
 ?4594 ???????? S????? 0:00 samba: task[rpc] pre-forked worker(2)
 ?4600 ???????? S????? 0:00 samba: task[rpc] pre-forked worker(3)


there are three rpc workers, good, where is written what is that they 
are serving ?


root at vdce:/home/damiano/work# rpcclient? -U "" -N -I 192.168.999.40
-c
srvinfo vdce
 ??????? VDCE?????????? Wk Sv PrQ Unx NT SNT Samba 
4.22.2-Debian-4.22.2+dfsg-1~bpo12+1
 ??????? platform_id???? :?????? 500
 ??????? os version????? :?????? 6.1
 ??????? server type???? :?????? 0x809a03


Il 2025-07-03 10:13 AM, Rowland Penny via samba ha
scritto:
> ps ax | grep 'samba' | grep 'rpc'