I have 2 AD DC and apparently there is something wrong with the replication. samba-tool drs showrepl returns kinda different information for the two: ---8<----------- First DC: Default-First-Site-Name\SAMBA DSA Options: 0x00000001 DSA object GUID: b19509be-c3ee-4a58-9fc9-afd61759a23f DSA invocationId: 4f30d79d-2e9c-4235-88a1-c258b8622d23 ==== INBOUND NEIGHBORS === DC=DomainDnsZones,DC=ad,DC=microsult,DC=de Default-First-Site-Name\VERDANDI via RPC DSA object GUID: a03bbb51-1dca-44ae-a4d9-7aa8cb4a1ace Last attempt @ Mon May 18 20:33:36 2015 CEST was successful 0 consecutive failure(s). Last success @ Mon May 18 20:33:36 2015 CEST [...] ==== OUTBOUND NEIGHBORS === DC=DomainDnsZones,DC=ad,DC=microsult,DC=de Default-First-Site-Name\VERDANDI via RPC DSA object GUID: a03bbb51-1dca-44ae-a4d9-7aa8cb4a1ace Last attempt @ NTTIME(0) was successful 0 consecutive failure(s). Last success @ NTTIME(0) [...] ==== KCC CONNECTION OBJECTS === Connection -- Connection name: 5ec3b776-4bad-4223-99b0-c489fc89a17b Enabled : TRUE Server DNS name : verdandi.ad.microsult.de Server DN name : CN=NTDS Settings,CN=VERDANDI,CN=Servers,CN=Default-First-Site-Name,CN=Sites,CN=Configuration,DC=ad,DC=microsult,DC=de TransportType: RPC options: 0x00000001 Warning: No NC replicated for Connection! Second DC: Default-First-Site-Name\VERDANDI DSA Options: 0x00000001 DSA object GUID: a03bbb51-1dca-44ae-a4d9-7aa8cb4a1ace DSA invocationId: 8bdb4f85-1da2-4f5a-b9a9-e8369d202745 ==== INBOUND NEIGHBORS === CN=Schema,CN=Configuration,DC=ad,DC=microsult,DC=de Default-First-Site-Name\SAMBA via RPC DSA object GUID: b19509be-c3ee-4a58-9fc9-afd61759a23f Last attempt @ Mon May 18 20:35:32 2015 CEST failed, result 5 (WERR_ACCESS_DENIED) 1147 consecutive failure(s). Last success @ Thu May 14 21:00:14 2015 CEST [...] ==== OUTBOUND NEIGHBORS === CN=Schema,CN=Configuration,DC=ad,DC=microsult,DC=de Default-First-Site-Name\SAMBA via RPC DSA object GUID: b19509be-c3ee-4a58-9fc9-afd61759a23f Last attempt @ NTTIME(0) was successful 0 consecutive failure(s). Last success @ NTTIME(0) [...] ==== KCC CONNECTION OBJECTS === Connection -- Connection name: ae027231-5c79-45d9-a9fd-1006cc1beb45 Enabled : TRUE Server DNS name : samba.ad.microsult.de Server DN name : CN=NTDS Settings,CN=SAMBA,CN=Servers,CN=Default-First-Site-Name,CN=Sites,CN=Configuration,DC=ad,DC=microsult,DC=de TransportType: RPC options: 0x00000001 Warning: No NC replicated for Connection! ---8<----------- I'm actually a little lost in correctly understanding INBOUND and OUTBOUND to begin with. But it seems that since last Thursday something bad is happening. Since everything keeps running currently, I'd appreciate any ideas to hunt down the core issue. Thanks for your help, - lars.