[Samba] accidentally upgraded DC to 4.17.3 ... didn't work

[Rowland Penny]

On 22/11/2022 08:43, Stefan G. Weichinger via samba wrote:
> Am 22.11.22 um 09:33 schrieb Rowland Penny via samba:
> 
>> To try and sort this out, the lines above what you have posted are 
>> required, you seem to have posted the lower portion of a python 
>> exception.
> 
> yes, ok. Browsing.
> 
> To me it seems that /etc/resolv.conf was overwritten by 
> systemd-resolved. I now edited /etc/systemd/resolved.conf to set the 2 
> DCs as DNSes etc

The best fix for that is to turn off systemd-resolved on a Samba DC and 
then create /etc/resolv.conf as you require it, that way, it cannot get 
changed.

> 
> I have to check/fix that on ADC1 as well.
> 
> There were lots of resolver-related messages:
> 
> /usr/sbin/samba_dnsupdate: dns.resolver.NoResolverConfiguration: 
> Resolver configuration could not be read
> 
> ---
> 
> but I don't have it OK yet:
> 
> Nov 22 09:38:27 adc2 samba[297691]:   /usr/sbin/samba_dnsupdate: raise 
> Exception("Timeout while waiting to contact a working DNS server while 
> looking for %s as %s" % (d, normalised_name))
> Nov 22 09:38:27 adc2 samba[297691]: [2022/11/22 09:38:27.768137,  0] 
> ../../lib/util/util_runcmd.c:355(samba_runcmd_io_handler)
> Nov 22 09:38:27 adc2 samba[297691]:   /usr/sbin/samba_dnsupdate: 
> Exception: Timeout while waiting to contact a working DNS server while 
> looking for A adc2.mytld
> 192.168.101.230 as adc2.my.tld.
> Nov 22 09:38:27 adc2 samba[297691]: [2022/11/22 09:38:27.796576,  0] 
> ../../source4/dsdb/dns/dns_update.c:85(dnsupdate_nameupdate_done)
> Nov 22 09:38:27 adc2 samba[297691]:   dnsupdate_nameupdate_done: Failed 
> DNS update with exit code 1

Yes, that is a dns problem.

> ^C
> root at adc2:~# dig adc2.my.tld
> ;; reply from unexpected source: 127.0.0.1#53, expected 127.0.0.53#53
> 
> root at adc2:~# cat /etc/resolv.conf
> # Dynamic resolv.conf(5) file for glibc resolver(3) generated by 
> resolvconf(8)
> #     DO NOT EDIT THIS FILE BY HAND -- YOUR CHANGES WILL BE OVERWRITTEN
> # 127.0.0.53 is the systemd-resolved stub resolver.
> # run "resolvectl status" to see details about the actual nameservers.
> 
> nameserver 127.0.0.53
> search arbeitsgruppe.my.tld

As I said, I suggest you turn off systemd-resolved, I also suggest that 
you check that netplan, network-manager, etc aren't getting in the way.

> 
> 
> root at adc2:~# cat /etc/systemd/resolved.conf
> 
> [Resolve]
> 
> DNS=10.0.0.230
> FallbackDNS=10.0.0.231
> Domains=my.tld
> 
> oh my
> 

See what I mean ;-)

Rowland