[Samba] Failed to find a writeable DC

[Rowland Penny]

On Fri, 10 Oct 2025 18:04:32 +0200 (CEST)
Fabrizio Rompani <fabrizio.rompani at yetopen.com> wrote:

> temporaly stopped firewall ( both ) 
> increased debug .
> Same error: 
> 
> thank's
> f
> 
> 
> 
> root at grants-dc:/var/lib/samba# samba-tool domain join s4ad.domain.org
> DC -U administrator --realm=S4AD.domain.ORG --debug=15 INFO: Current
> 
SNIP
> 00      org...). ....... Addrs = xx.xx.xx.xx at 389/grants finddcs: DNS
> SRV response 0 at 'xx.xx.xx.xx' ERROR: Failed to find a writeable DC
> for domain 's4ad.domain.org': The object was not found. File
> "/usr/lib/python3/dist-packages/samba/join.py", line 352, in find_dc
> ctx.cldap_ret = ctx.net.finddc(domain=domain,
> flags=nbt.NBT_SERVER_LDAP | nbt.NBT_SERVER_DS |
> nbt.NBT_SERVER_WRITABLE)
> ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
>           

It seems to be saying that it cannot find a DC in the 's4ad.domain.org'
dns domain, so, and these may probably be stupid questions, is there a
dns domain called 's4ad.domain.org', is there at least one RWDC in that
dns domain and can you ping the dns domain from the computer that you
are trying to join as a DC.

Does /etc/hostname contain the computers short hostname.

Does /etc/hosts have a line like this:

192.168.1.15 dc1.s4ad.domain.org dc1

Where:	192.168.1.15 is the computers ipaddress
	dc1 is the computers short hostname

Does /etc/resolv.conf look like this:

search s4ad.domain.org
nameserver 192.168.1.2

Where 192.168.1.2 is a DC in the s4ad.domain.org dns domain

Does /etc/krb5.conf have this as minimum:

[libdefaults]
    default_realm = S4AD.DOMAIN.ORG
    dns_lookup_realm = false
    dns_lookup_kdc = true

Finally, is everything in the same subnet e.g. 192.168.1.2/24

Rowland