Hi all! I have an AD domain with two DC's, DC3 (samba 4.20.4 from backports in a VM running debian 12) and DC2 (samba 4.18.9 in a VM running slackware 15.0) who holds the FSMO roles and I tried to replace DC2 with another host named DC2 (samba 4.20.5 from backports in a VM running debian 12). What I did was (in this order): * Shutdown both DC's * Snapshot both DC's disks * Brought back up both DC's * Verified that idmap.ldb on (old) DC2 and DC3 where in sync * Transfered the roles from DC2 (old) to DC3 * Demoted DC2 and shutdown the slackware 15.0 VM * Brought up the debian VM holding the (new) DC2 * Joined (new) DC2 to the domain as a DC * Copied idmap.ldb from DC3 to (new) DC2 * rsync'ed sysvol from DC3 to (new) DC2 * run net cache flush on (new) DC2 * start samba-ad-dc service on (new) DC2 * run samba-tool ntacl sysvol-reset on (new) DC2 While sysvol-reset was running i was doing some checks and found entries on DC3 stating Oct 15 07:31:25 dc3 samba[610]: [2024/10/15 07:31:25.243401, 0] source4/librpc/rpc/dcerpc_util.c:681(dcerpc_pipe_auth_recv) Oct 15 07:31:25 dc3 samba[610]: Failed to bind to uuid e3514235-4b06-11d1-ab04-00c04fc2dcd2 for ncacn_ip_tcp:192.168.1.3[49153,seal,krb5,target_hostname=25d3f929-0284-4f3f-a609-a869bb9b9722._msdcs.ad.samdom.com,target_principal=GC/dc2.ad.samdom.com/ad.samdom.com,abstract_syntax=e3514235-4b06-11d1-ab04-00c04fc2dcd2/0x00000004,localaddress=192.168.1.2] NT_STATUS_UNSUCCESSFUL I saw on a windows workstation that in the "Active directory sites and services" RSAT applet there wasn't a connection in the NTDS connections of DC3 so I manually created one to DC2 On (new) DC2 I verified the replication and the output of the samba-tool drs showrepl command was as follows Default-First-Site-Name\DC2 DSA Options: 0x00000001 DSA object GUID: 25d3f929-0284-4f3f-a609-a869bb9b9722 DSA invocationId: d7b7eea4-67e7-4dba-a338-acd99ac30dc9 ==== INBOUND NEIGHBORS === DC=ForestDnsZones,DC=ad,DC=samdom,DC=com Default-First-Site-Name\DC3 via RPC DSA object GUID: d2347f3c-1b9e-4ad5-a936-52c8cb1c0fc3 Last attempt @ Tue Oct 15 07:35:41 2024 -03 was successful 0 consecutive failure(s). Last success @ Tue Oct 15 07:35:41 2024 -03 DC=DomainDnsZones,DC=ad,DC=samdom,DC=com Default-First-Site-Name\DC3 via RPC DSA object GUID: d2347f3c-1b9e-4ad5-a936-52c8cb1c0fc3 Last attempt @ Tue Oct 15 07:35:41 2024 -03 was successful 0 consecutive failure(s). Last success @ Tue Oct 15 07:35:41 2024 -03 CN=Schema,CN=Configuration,DC=ad,DC=samdom,DC=com Default-First-Site-Name\DC3 via RPC DSA object GUID: d2347f3c-1b9e-4ad5-a936-52c8cb1c0fc3 Last attempt @ Tue Oct 15 07:35:42 2024 -03 was successful 0 consecutive failure(s). Last success @ Tue Oct 15 07:35:42 2024 -03 CN=Configuration,DC=ad,DC=samdom,DC=com Default-First-Site-Name\DC3 via RPC DSA object GUID: d2347f3c-1b9e-4ad5-a936-52c8cb1c0fc3 Last attempt @ Tue Oct 15 07:35:42 2024 -03 was successful 0 consecutive failure(s). Last success @ Tue Oct 15 07:35:42 2024 -03 DC=ad,DC=samdom,DC=com Default-First-Site-Name\DC3 via RPC DSA object GUID: d2347f3c-1b9e-4ad5-a936-52c8cb1c0fc3 Last attempt @ Tue Oct 15 07:35:42 2024 -03 was successful 0 consecutive failure(s). Last success @ Tue Oct 15 07:35:42 2024 -03 ==== OUTBOUND NEIGHBORS === ==== KCC CONNECTION OBJECTS === Connection -- Connection name: 0ec9a878-eeff-4b55-8015-5529b4013326 Enabled : TRUE Server DNS name : dc3.ad.samdom.com Server DN name : CN=NTDS Settings,CN=DC3,CN=Servers,CN=Default-First-Site-Name,CN=Sites,CN=Configuration,DC=ad,DC=samdom,DC=com TransportType: RPC options: 0x00000001 Warning: No NC replicated for Connection! Connection -- Connection name: DC3 Enabled : TRUE Server DNS name : dc3.ad.samdom.com Server DN name : CN=NTDS Settings,CN=DC3,CN=Servers,CN=Default-First-Site-Name,CN=Sites,CN=Configuration,DC=ad,DC=samdom,DC=com TransportType: RPC options: 0x00000000 Warning: No NC replicated for Connection! The output of samba-tool drs showrepl on DC3 looked like this Default-First-Site-Name\DC3 DSA Options: 0x00000001 DSA object GUID: d2347f3c-1b9e-4ad5-a936-52c8cb1c0fc3 DSA invocationId: 9e1fd29b-8f65-4f75-af93-00b358b046d2 ==== INBOUND NEIGHBORS === DC=ForestDnsZones,DC=ad,DC=samdom,DC=com Default-First-Site-Name\DC2 via RPC DSA object GUID: 25d3f929-0284-4f3f-a609-a869bb9b9722 Last attempt @ Tue Oct 15 07:36:24 2024 -03 failed, result 31 (WERR_GEN_FAILURE) 3 consecutive failure(s). Last success @ NTTIME(0) DC=DomainDnsZones,DC=ad,DC=samdom,DC=com Default-First-Site-Name\DC2 via RPC DSA object GUID: 25d3f929-0284-4f3f-a609-a869bb9b9722 Last attempt @ Tue Oct 15 07:36:24 2024 -03 failed, result 31 (WERR_GEN_FAILURE) 3 consecutive failure(s). Last success @ NTTIME(0) CN=Schema,CN=Configuration,DC=ad,DC=samdom,DC=com Default-First-Site-Name\DC2 via RPC DSA object GUID: 25d3f929-0284-4f3f-a609-a869bb9b9722 Last attempt @ Tue Oct 15 07:36:24 2024 -03 failed, result 31 (WERR_GEN_FAILURE) 3 consecutive failure(s). Last success @ NTTIME(0) CN=Configuration,DC=ad,DC=samdom,DC=com Default-First-Site-Name\DC2 via RPC DSA object GUID: 25d3f929-0284-4f3f-a609-a869bb9b9722 Last attempt @ Tue Oct 15 07:36:25 2024 -03 failed, result 31 (WERR_GEN_FAILURE) 3 consecutive failure(s). Last success @ NTTIME(0) DC=ad,DC=samdom,DC=com Default-First-Site-Name\DC2 via RPC DSA object GUID: 25d3f929-0284-4f3f-a609-a869bb9b9722 Last attempt @ Tue Oct 15 07:36:25 2024 -03 failed, result 31 (WERR_GEN_FAILURE) 3 consecutive failure(s). Last success @ NTTIME(0) ==== OUTBOUND NEIGHBORS === DC=ForestDnsZones,DC=ad,DC=samdom,DC=com Default-First-Site-Name\DC2 via RPC DSA object GUID: 25d3f929-0284-4f3f-a609-a869bb9b9722 Last attempt @ Tue Oct 15 07:39:18 2024 -03 failed, result 31 (WERR_GEN_FAILURE) 44 consecutive failure(s). Last success @ NTTIME(0) DC=DomainDnsZones,DC=ad,DC=samdom,DC=com Default-First-Site-Name\DC2 via RPC DSA object GUID: 25d3f929-0284-4f3f-a609-a869bb9b9722 Last attempt @ Tue Oct 15 07:39:18 2024 -03 failed, result 31 (WERR_GEN_FAILURE) 44 consecutive failure(s). Last success @ NTTIME(0) CN=Schema,CN=Configuration,DC=ad,DC=samdom,DC=com Default-First-Site-Name\DC2 via RPC DSA object GUID: 25d3f929-0284-4f3f-a609-a869bb9b9722 Last attempt @ Tue Oct 15 07:39:18 2024 -03 failed, result 31 (WERR_GEN_FAILURE) 44 consecutive failure(s). Last success @ NTTIME(0) CN=Configuration,DC=ad,DC=samdom,DC=com Default-First-Site-Name\DC2 via RPC DSA object GUID: 25d3f929-0284-4f3f-a609-a869bb9b9722 Last attempt @ Tue Oct 15 07:39:18 2024 -03 failed, result 31 (WERR_GEN_FAILURE) 44 consecutive failure(s). Last success @ NTTIME(0) DC=ad,DC=samdom,DC=com Default-First-Site-Name\DC2 via RPC DSA object GUID: 25d3f929-0284-4f3f-a609-a869bb9b9722 Last attempt @ Tue Oct 15 07:39:19 2024 -03 failed, result 31 (WERR_GEN_FAILURE) 44 consecutive failure(s). Last success @ NTTIME(0) ==== KCC CONNECTION OBJECTS === Connection -- Connection name: 2aea5c8f-b9b5-45da-bf46-e3d775554bd1 Enabled : TRUE Server DNS name : dc2.ad.samdom.com Server DN name : CN=NTDS Settings,CN=DC2,CN=Servers,CN=Default-First-Site-Name,CN=Sites,CN=Configuration,DC=ad,DC=samdom,DC=com TransportType: RPC options: 0x00000001 Warning: No NC replicated for Connection! By the time I got to this point my window of opportunity to perform this change of DC's was closing so I reverted to the snapshots taken before anything and everything is working OK but next week I'm going to be attempting to change this DC again and I was wondering if someone could see what might have gone wrong because I certainly can't. Thanks in advance! Best regards, Dave.