samba - Aug 2022 - After a power outage Samba DNS is no longer working properly

OS: Ubuntu 20.04.3
   Samba version: 4.15.2 from Louis' repo

We suffered a power outage after which Samba DNS resolution no longer 
works and I can't figure out why.  The domain controller continues to be 
aware of its client machines:

root at samba-dc:~# samba-tool dns query samba-dc ea.my_org.org ea124 A -U 
Administrator
Password for [EA\Administrator]:
   Name=, Records=1, Children=0
     A: 172.18.90.124 (flags=f0, serial=110, ttl=1200)


root at samba-dc:~# samba-tool dns query samba-dc 90.18.172.in-addr.arpa 
124 PTR -U Administrator
Password for [EA\Administrator]:
   Name=, Records=1, Children=0
     PTR: EA124.ea.my_org.org (flags=f0, serial=7, ttl=900)

However, on the Windows 10 clients (specifically ea124)

   net use G: \\data2\share

gives a characteristically cryptic Microsoft error message: Error 53
which turns out to mean it can't resolve the host name.  If I substitute 
the share server's IP address:

   net use G: \\127.18.90.30\share

then the mount executes as one would expect.

The Wiki page here: https://wiki.samba.org/index.php/DNS_Administration

is very sparse on details of how one would go about debugging or 
repairing this issue.  I seem to recall people running into this on much 
larger networks than mine, but googling and searching the list didn't 
bring up any useful information.

Anyone have any ideas?

Oh, I should add to this that is searching the web I found this command:

   root at samba-dc:~# samba_dnsupdate --verbose --all-names

That results in, among other things, errors that look like this:
----------------------------------------------
   ; TSIG error with server: tsig verify failure
Failed nsupdate: 2
update(nsupdate): SRV 
_ldap._tcp.Default-First-Site-Name._sites.ForestDnsZones.ea.my_org.org 
samba-dc.ea.my_org.org 389
Calling nsupdate for SRV 
_ldap._tcp.Default-First-Site-Name._sites.ForestDnsZones.ea.my_orgs.org 
samba-dc.ea.my_org.org 389 (add)
Successfully obtained Kerberos ticket to DNS/samba-dc.ea.myorg.org as 
SAMBA-DC$
Outgoing update query:
;; ->>HEADER<<- opcode: UPDATE, status: NOERROR, id:      0
;; flags:; ZONE: 0, PREREQ: 0, UPDATE: 0, ADDITIONAL: 0
;; UPDATE SECTION:
_ldap._tcp.Default-First-Site-Name._sites.ForestDnsZones.ea.my_org.org. 
900 IN SRV 0 100 389 samba-dc.ea.my_org.org.

; TSIG error with server: tsig verify failure
Failed nsupdate: 2
Failed update of 29 entries
----------------------------------------------

<rant>I ran a Samba 3 server for this org for 12 years. In their 
previous locations they had power outages on an almost weekly basis and 
yet Samba 3 *never* crashed and burned.  Now running Samba 4 in a new 
location, and the very first time there's a power hiccup it falls part. 
  There is literally nothing which should make the software fail like 
this.</rant>

On 8/26/22 15:05, Patrick Goetz via samba wrote:
> 
>  ? OS: Ubuntu 20.04.3
>  ? Samba version: 4.15.2 from Louis' repo
> 
> We suffered a power outage after which Samba DNS resolution no longer 
> works and I can't figure out why.? The domain controller continues to
be
> aware of its client machines:
> 
> root at samba-dc:~# samba-tool dns query samba-dc ea.my_org.org ea124 A -U 
> Administrator
> Password for [EA\Administrator]:
>  ? Name=, Records=1, Children=0
>  ??? A: 172.18.90.124 (flags=f0, serial=110, ttl=1200)
> 
> 
> root at samba-dc:~# samba-tool dns query samba-dc 90.18.172.in-addr.arpa 
> 124 PTR -U Administrator
> Password for [EA\Administrator]:
>  ? Name=, Records=1, Children=0
>  ??? PTR: EA124.ea.my_org.org (flags=f0, serial=7, ttl=900)
> 
> However, on the Windows 10 clients (specifically ea124)
> 
>  ? net use G: \\data2\share
> 
> gives a characteristically cryptic Microsoft error message: Error 53
> which turns out to mean it can't resolve the host name.? If I
substitute
> the share server's IP address:
> 
>  ? net use G: \\127.18.90.30\share
> 
> then the mount executes as one would expect.
> 
> The Wiki page here: 
>
https://nam12.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwiki.samba.org%2Findex.php%2FDNS_Administration&amp;data=05%7C01%7C%7C72149244adb241bddc9d08da87a0b21e%7C31d7e2a5bdd8414e9e97bea998ebdfe1%7C0%7C0%7C637971421504331373%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&amp;sdata=UhNlXcoit6hdPl%2Bs2HteeiG6hYR%2FAavVPN0eypf8jSc%3D&amp;reserved=0
> 
> 
> is very sparse on details of how one would go about debugging or 
> repairing this issue.? I seem to recall people running into this on much 
> larger networks than mine, but googling and searching the list didn't 
> bring up any useful information.
> 
> Anyone have any ideas?
> 
> 
>