Hi Team, I am running Samba 4.19.4 on bookworm, clients are Windows 10 22H2 with automatic win-updates enabled. The [global] section of smb.conf: [global] ??????? netbios name = DC01 ??????? realm = EXAMPLE.COM ??????? server role = active directory domain controller ??????? server services = -dns ??????? workgroup = EXAMPLE ??????? kerberos method = secrets and keytab ??????? kerberos encryption types = strong ??????? rpc server dynamic port range = 50000-55000 ??????? ntlm auth = mschapv2-and-ntlmv2-only ??????? disable netbios = yes ??????? template homedir = /home/%U ??????? template shell = /bin/bash ??????? tls enabled = yes ??????? tls priority = NONE:+SECURE256:-VERS-ALL:+VERS-TLS1.2:+VERS-TLS1.3 ??????? tls cafile = /etc/ssl/certs/ca.pem ??????? tls keyfile = /var/lib/samba/private/tls/dc01.example.com.key ??????? tls certfile = /etc/ssl/certs/dc01.example.com.crt ??????? load printers = no ??????? printing = bsd ??????? printcap name = /dev/null ??????? disable spoolss = yes ??????? smb ports = 445 ??????? smbd profiling level = on ??????? server min protocol = SMB3_11 ??????? client min protocol = SMB3_11 ??????? restrict anonymous = 2 ??????? map acl inherit = yes ??????? panic action = /usr/share/samba/panic-action %d ??????? server smb encrypt = desired ??????? interfaces = lo eth0 ??????? bind interfaces only = yes ??????? allow dns updates = disabled ??????? ldap server require strong auth = yes ??????? ldap ssl = start tls ??????? dedicated keytab file = /var/lib/samba/private/secrets.keytab ??????? log level = 3 winbind:2 auth_json_audit:3@/var/log/samba/audit_auth.log ??????? full_audit:success = open fsync_recv fsync_send ftruncate pwrite pwrite_recv pwrite_send renameat unlinkat write ??????? full_audit:failure = open pread read ??????? full_audit:prefix = samba: IP=%I|USER=%u|MACHINE=%m|VOLUME=%S ??????? full_audit:facility = local6 ??????? full_audit:priority = NOTICE ??????? idmap config *:range = 1000000-1999999 ??????? host msdfs = yes ??????? max log size = 0 ??????? vfs objects = dfs_samba4, acl_xattr, full_audit ??????? tls crlfile = /etc/ssl/certs/crl.pem ??????? tls dh params file = /etc/ssl/certs/dhparam.pem Now a user has an interesting issue, she can login on Windows without issues but when changing the password Windows complains the password is wrong. In log.samba on the DC, I see this: [2024/02/22 12:15:57.646475,? 3] auth/auth_log.c:858(log_authentication_event_human_readable) ? Auth: [Kerberos KDC,ENC-TS Pre-authentication] user [(null)]\[user1 at EXAMPLE] at [Thu, 22 Feb 2024 12:15:57.646467 CET] with [aes256-cts-hmac-sha1-96] status [NT_STATUS_OK] workstation [(null)] remote host [ipv4:192.168.0.211:50757] became [EXAMPLE]\[user1] [S-1-5-21-1366037735-1163107043-795354949-1003]. local host [NULL] [2024/02/22 12:15:57.646564,? 3] source4/auth/kerberos/krb5_init_context.c:90(smb_krb5_debug_wrapper) ? Kerberos: heim_audit_vaddkv(): kv pair[0] elapsed=0.020364 [2024/02/22 12:15:57.646571,? 3] source4/auth/kerberos/krb5_init_context.c:90(smb_krb5_debug_wrapper) ? Kerberos: AS-REQ SUCCESS ipv4:192.168.0.211:50757 user1 at EXAMPLE kadmin/changepw at EXAMPLE pa=ENC-TS etype=18/18 canon_client_name=user1 at EXAMPLE.COM pac_attributes=1 pa-etype=18 client-pa=ENC-TS,128 end=1708600677 auth=1708600557 etypes=18,17,23,24,-135,3 renew=1709205357 pa-succeeded-kvno=19 reqaddrs=TYPE_20:50433131312020202020202020202020 elapsed=0.020364 flags=renewable-ok,canonicalize,renewable,forwardable [2024/02/22 12:15:57.647409,? 3] source4/samba/service_stream.c:67(stream_terminate_connection) ? stream_terminate_connection: Terminating connection - 'kdc_tcp_call_loop: tstream_read_pdu_blob_recv() - NT_STATUS_CONNECTION_DISCONNECTED' [2024/02/22 12:15:57.648670,? 3] auth/kerberos/kerberos_pac.c:413(kerberos_decode_pac) ? Found account name from PAC: user1 [User One] [2024/02/22 12:15:57.653002,? 3] lib/ldb-samba/ldb_wrap.c:332(ldb_wrap_connect) ? ldb_wrap open of privilege.ldb [2024/02/22 12:15:57.653253,? 1] source4/kdc/kpasswd-service-heimdal.c:297(kpasswd_handle_request) ? kpasswd_handle_request: String conversion failed! [2024/02/22 12:15:57.654054,? 3] source4/samba/service_stream.c:67(stream_terminate_connection) ? stream_terminate_connection: Terminating connection - 'kdc_tcp_call_loop: tstream_read_pdu_blob_recv() - NT_STATUS_CONNECTION_DISCONNECTED' This is interesting: kpasswd_handle_request: String conversion failed! It is the only clue in the server logging that something is not alright, as far as I can see. The audit_auth.log does not report any issues: ? {"timestamp": "2024-02-22T12:15:33.140169+0100", "type": "Authentication", "Authentication": {"version": {"major": 1, "minor": 3}, "eventId": 4624, "logonId": "19e950ca59b91207", "logonType": 3, "status" : "NT_STATUS_OK", "localAddress": null, "remoteAddress": "ipv4:192.168.0.211:50753", "serviceDescription": "Kerberos KDC", "authDescription": "ENC-TS Pre-authentication", "clientDomain": null, "clientAccou nt": "user1 at EXAMPLE", "workstation": null, "becameAccount": "user1", "becameDomain": "EXAMPLE", "becameSid": "S-1-5-21-1366037735-1163107043-795354949-1003", "mappedAccount": "user1", "mappedDo main": "EXAMPLE", "netlogonComputer": null, "netlogonTrustAccount": null, "netlogonNegotiateFlags": "0x00000000", "netlogonSecureChannelType": 0, "netlogonTrustAccountSid": null, "passwordType": "aes256 -cts-hmac-sha1-96", "clientPolicyAccessCheck": null, "serverPolicyAccessCheck": null, "duration": 13086}} ? {"timestamp": "2024-02-22T12:15:33.150004+0100", "type": "KDC Authorization", "KDC Authorization": {"version": {"major": 1, "minor": 0}, "status": "NT_STATUS_OK", "localAddress": null, "remoteAddress": " ipv4:192.168.0.211:50754", "serviceDescription": "host/pc11.exmaple.com at EXAMPLE.COM", "authType": "TGS-REQ with Ticket-Granting Ticket", "domain": "EXAMPLE", "account": "user1", "sid": "S-1-5-2 1-1366037735-1163107043-795354949-1003", "logonServer": "DC01", "authTime": "2024-02-22T12:15:33.141814+0100", "serverPolicyAccessCheck": null}} ? {"timestamp": "2024-02-22T12:15:57.646491+0100", "type": "Authentication", "Authentication": {"version": {"major": 1, "minor": 3}, "eventId": 4624, "logonId": "979e535fc7a6536d", "logonType": 3, "status" : "NT_STATUS_OK", "localAddress": null, "remoteAddress": "ipv4:192.168.0.211:50757", "serviceDescription": "Kerberos KDC", "authDescription": "ENC-TS Pre-authentication", "clientDomain": null, "clientAccou nt": "user1 at EXAMPLE", "workstation": null, "becameAccount": "user1", "becameDomain": "EXAMPLE", "becameSid": "S-1-5-21-1366037735-1163107043-795354949-1003", "mappedAccount": "user1", "mappedDo main": "EXAMPLE", "netlogonComputer": null, "netlogonTrustAccount": null, "netlogonNegotiateFlags": "0x00000000", "netlogonSecureChannelType": 0, "netlogonTrustAccountSid": null, "passwordType": "aes256 -cts-hmac-sha1-96", "clientPolicyAccessCheck": null, "serverPolicyAccessCheck": null, "duration": 20296}} Any ideas what is going wrong here? - Kees.