[Samba] samba-tool drs showrepl shows WERR_BAD_NETPATH

Wed Aug 24 10:30:27 UTC 2016

Am 23.08.2016 um 15:36 wrote Heinz Allerberger via samba:
> Hello there,
>
> I have a problem with replication between two domain controllers, dc1 
> and dc2.
> Distribution: Debian 8.5
> Samba-Distribution: sernet-samba 4.3.11-14
>
> The replication on dc2 working fine without any failures.
> But the synchronization on dc1 gives the failure "WERR_BAD_NETPATH".
>
> Because the message "BAD_NETPATH" I checked the DNS-resolution:
> ==========================================
> root at dc1:~#host dc1
> dc1.mydomain.uni-frankfurt.de has address 192.168.151.230
>
> root at dc1:~# host dc2
> dc2.mydomain.uni-frankfurt.de has address 192.168.151.231
>
> host -t SRV _kerberos._tcp.mydomain.uni-frankfurt.de
> _kerberos._tcp.mydomain.uni-frankfurt.de has SRV record 0 100 88 
> dc1.mydomain.uni-frankfurt.de.
> _kerberos._tcp.mydomain.uni-frankfurt.de has SRV record 0 100 88 
> dc2.mydomain.uni-frankfurt.de.
>
> root at dc1:~# host -t SRV _ldap._tcp.mydomain.uni-frankfurt.de
> _ldap._tcp.mydomain.uni-frankfurt.de has SRV record 0 100 389 
> dc1.mydomain.uni-frankfurt.de.
> _ldap._tcp.mydomain.uni-frankfurt.de has SRV record 0 100 389 
> dc2.mydomain.uni-frankfurt.de.
>
>
> OUTBOUND-replication on dc1 show me any failures:
> ================================
> root at dc1:~# samba-tool drs showrepl
> Default-First-Site-Name\DC1
> DSA Options: 0x00000001
> DSA object GUID: 1ae9c878-4d33-417a-9995-061189db4f8d
> DSA invocationId: dff09274-9c24-49c6-beb5-647561d5d893
>
> ==== INBOUND NEIGHBORS ====
>
> DC=ForestDnsZones,DC=mydomain,DC=uni-frankfurt,DC=de
>         Default-First-Site-Name\dc2 via RPC
>                 DSA object GUID: e4da82c7-5d42-4011-8733-00a9dffb6633
>                 Last attempt @ Mon Aug 22 16:19:25 2016 CEST was 
> successful
>                 0 consecutive failure(s).
>                 Last success @ Mon Aug 22 16:19:25 2016 CEST
> ....
>
> ==== OUTBOUND NEIGHBORS ====
>
> DC=ForestDnsZones,DC=mydomain,DC=uni-frankfurt,DC=de
>         Default-First-Site-Name\dc2 via RPC
>                 DSA object GUID: e4da82c7-5d42-4011-8733-00a9dffb6633
>                 Last attempt @ Mon Aug 22 16:20:14 2016 CEST failed, 
> result 53 (WERR_BAD_NETPATH)
>                 37 consecutive failure(s).
>                 Last success @ NTTIME(0)
>
> DC=DomainDnsZones,DC=mydomain,DC=uni-frankfurt,DC=de
>         Default-First-Site-Name\dc2 via RPC
>                 DSA object GUID: e4da82c7-5d42-4011-8733-00a9dffb6633
>                 Last attempt @ Mon Aug 22 16:20:14 2016 CEST failed, 
> result 53 (WERR_BAD_NETPATH)
>                 37 consecutive failure(s).
>                 Last success @ NTTIME(0)
>
> DC=mydomain,DC=uni-frankfurt,DC=de
>         Default-First-Site-Name\dc2 via RPC
>                 DSA object GUID: e4da82c7-5d42-4011-8733-00a9dffb6633
>                 Last attempt @ Mon Aug 22 16:20:14 2016 CEST failed, 
> result 53 (WERR_BAD_NETPATH)
>                 37 consecutive failure(s).
>                 Last success @ NTTIME(0)
>
> CN=Schema,CN=Configuration,DC=mydomain,DC=uni-frankfurt,DC=de
>         Default-First-Site-Name\dc2 via RPC
>                 DSA object GUID: e4da82c7-5d42-4011-8733-00a9dffb6633
>                 Last attempt @ Mon Aug 22 16:20:14 2016 CEST failed, 
> result 53 (WERR_BAD_NETPATH)
>                 37 consecutive failure(s).
>                 Last success @ NTTIME(0)
>
> CN=Configuration,DC=mydomain,DC=uni-frankfurt,DC=de
>         Default-First-Site-Name\dc2 via RPC
>                 DSA object GUID: e4da82c7-5d42-4011-8733-00a9dffb6633
>                 Last attempt @ Mon Aug 22 16:20:14 2016 CEST failed, 
> result 53 (WERR_BAD_NETPATH)
>                 37 consecutive failure(s).
>                 Last success @ NTTIME(0)
>
> ==== KCC CONNECTION OBJECTS ====
>
> Connection --
>         Connection name: 1367f590-6672-4807-bc27-2ac167d40a88
>         Enabled        : TRUE
>         Server DNS name : dc2.mydomain.uni-frankfurt.de
>         Server DN name  : CN=NTDS 
> Settings,CN=dc2,CN=Servers,CN=Default-First-Site-Name,CN=Sites,CN=Configuration,DC=mydomain,DC=uni-frankfurt,DC=de
>                 TransportType: RPC
>                 options: 0x00000001
> Warning: No NC replicated for Connection!
>
> Best regards
> Heinz
>

Solved!
For all who have a similar problem with replication:
================================
I had a look to the /var/log/samba/log.samba on both servers, dc1 and 
dc2 and I found out,
that the DNS update failed on server dc2 sins a time where the dc1 
really was not alive.
This would be normal.

The failure is that DNS update has not working forward again, when the 
dc1 was back into the network
and was alive again.
This my be a debility in Samba and the developer could have a look about 
this...

I could fixed it, with a reboot from dc2. Now it is working!

dc2 in /var/log/samba/log.samba:
=====================
.....dns update failed
[2016/08/19 14:47:31.646907,  0] 
../source4/dsdb/dns/dns_update.c:294(dnsupdate_nameupdate_done)
   ../source4/dsdb/dns/dns_update.c:294: Failed DNS update - 
NT_STATUS_IO_TIMEOUT
[2016/08/19 14:48:59.829660,  0] ../source4/smbd/server.c:121(sig_term)
   Exiting pid 24381 on SIGTERM
[2016/08/19 14:50:59.870435,  0] ../source4/smbd/server.c:121(sig_term)
   Exiting pid 24417 on SIGTERM
[2016/08/19 14:52:59.898571,  0] ../source4/smbd/server.c:121(sig_term)
   Exiting pid 24434 on SIGTERM
[2016/08/19 14:56:16.929109,  0] 
../source4/rpc_server/common/forward.c:51(dcesrv_irpc_forward_callback)
   IRPC callback failed for DsReplicaSync - NT_STATUS_OBJECT_NAME_NOT_FOUND
[2016/08/19 14:56:16.947998,  0] 
../source4/rpc_server/common/forward.c:51(dcesrv_irpc_forward_callback)
   IRPC callback failed for DsReplicaSync - NT_STATUS_OBJECT_NAME_NOT_FOUND

....... the server dc1 was back since 4 minutes
[2016/08/19 15:00:22.673835,  0] 
../source4/rpc_server/common/forward.c:51(dcesrv_irpc_forward_callback)
   IRPC callback failed for DsReplicaSync - NT_STATUS_OBJECT_NAME_NOT_FOUND
[2016/08/19 15:00:22.687150,  0] 
../source4/rpc_server/common/forward.c:51(dcesrv_irpc_forward_callback)
   IRPC callback failed for DsReplicaSync - NT_STATUS_OBJECT_NAME_NOT_FOUND

.......but dns update failed and failed and runs in a loop until yesterday
[2016/08/23 16:58:45.284777,  0] 
../source4/rpc_server/common/forward.c:51(dcesrv_irpc_forward_callback)
   IRPC callback failed for DsReplicaSync - NT_STATUS_OBJECT_NAME_NOT_FOUND
[2016/08/23 16:58:45.292703,  0] 
../source4/rpc_server/common/forward.c:51(dcesrv_irpc_forward_callback)

.......reboot
[2016/08/23 16:58:49.791606,  0] ../source4/smbd/server.c:116(sig_term)
   SIGTERM: killing children
[2016/08/23 16:59:00.794333,  0] 
../source4/smbd/server.c:372(binary_smbd_main)
   samba version 4.3.11-SerNet-Debian-14.jessie started.
   Copyright Andrew Tridgell and the Samba Team 1992-2015
[2016/08/23 16:59:01.538600,  0] 
../source4/smbd/server.c:490(binary_smbd_main)
   samba: using 'standard' process model
[2016/08/23 16:59:01.563627,  0] 
../lib/util/become_daemon.c:124(daemon_ready)
   STATUS=daemon 'samba' finished starting up and ready to serve connections
....NOW IT RUNS AND NO FAILURE SINCE THE REBOOT

Here you can see when the dc1 was down...
dc1 /var/log/samba/log.samba:
====================
...it shutded down
[2016/08/19 14:41:44.792623,  0] ../source4/smbd/server.c:121(sig_term)
   Exiting pid 817 on SIGTERM

it started up
[2016/08/19 14:56:09.521374,  0] 
../source4/smbd/server.c:372(binary_smbd_main)
   samba version 4.3.11-SerNet-Debian-14.jessie started.
   Copyright Andrew Tridgell and the Samba Team 1992-2015
[2016/08/19 14:56:10.425955,  0] 
../source4/smbd/server.c:490(binary_smbd_main)
   samba: using 'standard' process model
[2016/08/19 14:56:10.746602,  0] 
../lib/util/become_daemon.c:124(daemon_ready)
   STATUS=daemon 'samba' finished starting up and ready to serve connections

I hope I can help other Samba-Users with this information.
Heinz