Running “samba-tool drs uptodateness” in any DC shows this message for every DC: Missing dn CN=DC01,CN=Servers,CN=Default-First-Site-Name,CN=Sites,CN=Configuration,<REMOVED> from UTD vector for dsa CN=DC11,CN=Servers,CN=Default-First-Site-Name,CN=Sites,CN=Configuration,<REMOVED> Missing dn CN=DC05,CN=Servers,CN=Porto,CN=Sites,CN=Configuration,<REMOVED> from UTD vector for dsa CN=DC11,CN=Servers,CN=Default-First-Site-Name,CN=Sites,CN=Configuration,<REMOVED> Missing dn CN=DC09,CN=Servers,CN=Funchal,CN=Sites,CN=Configuration,<REMOVED> from UTD vector for dsa CN=DC11,CN=Servers,CN=Default-First-Site-Name,CN=Sites,CN=Configuration,<REMOVED> Missing dn CN=DC04,CN=Servers,CN=Lisboa,CN=Sites,CN=Configuration,<REMOVED> from UTD vector for dsa CN=DC11,CN=Servers,CN=Default-First-Site-Name,CN=Sites,CN=Configuration,<REMOVED> Missing dn CN=DC06,CN=Servers,CN=Coimbra,CN=Sites,CN=Configuration,<REMOVED> from UTD vector for dsa CN=DC11,CN=Servers,CN=Default-First-Site-Name,CN=Sites,CN=Configuration,<REMOVED> Missing dn CN=DC07,CN=Servers,CN=Evora,CN=Sites,CN=Configuration,<REMOVED> from UTD vector for dsa CN=DC11,CN=Servers,CN=Default-First-Site-Name,CN=Sites,CN=Configuration,<REMOVED> Missing dn CN=DC02,CN=Servers,CN=Default-First-Site-Name,CN=Sites,CN=Configuration,<REMOVED> from UTD vector for dsa CN=DC11,CN=Servers,CN=Default-First-Site-Name,CN=Sites,CN=Configuration,<REMOVED> Missing dn CN=DC08,CN=Servers,CN=Faro,CN=Sites,CN=Configuration,<REMOVED> from UTD vector for dsa CN=DC11,CN=Servers,CN=Default-First-Site-Name,CN=Sites,CN=Configuration,<REMOVED> Missing dn CN=DC10,CN=Servers,CN=Angra,CN=Sites,CN=Configuration,<REMOVED> from UTD vector for dsa CN=DC11,CN=Servers,CN=Default-First-Site-Name,CN=Sites,CN=Configuration,<REMOVED> Missing dn CN=DC03,CN=Servers,CN=Lisboa,CN=Sites,CN=Configuration,<REMOVED> from UTD vector for dsa CN=DC11,CN=Servers,CN=Default-First-Site-Name,CN=Sites,CN=Configuration,<REMOVED> DOMAIN maximum: 289 median: 19.0 failure: 10 CONFIGURATION maximum: 650 median: 23.0 failure: 10 SCHEMA maximum: 672 median: 26.0 failure: 10 DNSDOMAIN maximum: 66 median: 2.0 failure: 10 DNSFOREST maximum: 707 median: 28.0 failure: 10 Replication works between all sites/DC's including DC11 which is running MS Windows 2008R2. root@DC01:~# samba-tool dbcheck --cross-ncs --fix Checking 22666 objects Checked 22666 objects (0 errors) This issue was discussed here: https://lists.samba.org/archive/samba/2022-July/241259.html
Note, the messages above were generated with an effective backport of ffa84f2e5d335626b5f7311af8d2a7056b3e5c6f to 4.15. Standard 4.15 would mention which DC has the missing records (DC11 in this case).