[Samba] tons of dns errors in log.samba

[Adam Xu]

Hi samba devs

My samba AD DC has worked for several years. I upgrade it from 4.6 to 
4.7 to 4.8 ....and now it's version is 4.12.10.

My OS is centos7 and I use the sernet samba repo.

Yesterday, I saw that my log.samba file was very large. tons of errors like:

[2020/11/25 08:35:09.299194,  1] 
../../source4/dns_server/dns_query.c:1141(dns_server_process_query_got_auth)
   dns_server_process_query_got_auth: Failed to add SOA record: 
WERR_DNS_ERROR_RCODE_FORMAT_ERROR
[2020/11/25 08:35:09.315638,  1] 
../../source4/dns_server/dns_query.c:1141(dns_server_process_query_got_auth)
   dns_server_process_query_got_auth: Failed to add SOA record: 
WERR_DNS_ERROR_RCODE_FORMAT_ERROR
[2020/11/25 08:35:09.733265,  1] 
../../source4/dns_server/dns_query.c:1141(dns_server_process_query_got_auth)
   dns_server_process_query_got_auth: Failed to add SOA record: 
WERR_DNS_ERROR_RCODE_FORMAT_ERROR
[2020/11/25 08:35:09.822746,  1] 
../../source4/dns_server/dns_query.c:1141(dns_server_process_query_got_auth)
   dns_server_process_query_got_auth: Failed to add SOA record: 
WERR_DNS_ERROR_RCODE_FORMAT_ERROR

about 3 log entries per second.

here's the smb.conf file:

[global]
     netbios name = DC1
     realm = EXAMPLE.COM
     workgroup = EXAMPLE
     dns forwarder = 119.29.29.29 8.8.4.4
     server role = active directory domain controller
     idmap_ldb:use rfc2307 = yes
     rpc server port = 49152
     rpc server port:netlogon = 49153
     rpc server port:drsuapi = 49154
     log level = 1 auth_json_audit:3@/var/log/samba/auth.log
     ntlm auth = mschapv2-and-ntlmv2-only

[netlogon]
     path = /var/lib/samba/sysvol/adagene.cn/scripts
     read only = No

[sysvol]
     path = /var/lib/samba/sysvol
     read only = No

If I blocked the port 53, the error log will stop.

although there are tons of dns errors, my AD works OK now.

Can anyone tell me what causes so many error logs. Is that matters?

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