This is what repadmin /showrepl looks like on the Windows DC
Repadmin: running command /showrepl against full DC localhost
Default-First-Site-Name\SERVER1
DSA Options: IS_GC
Site Options: (none)
DSA object GUID: 2f9f90df-33e0-445a-857a-6f0d34427e51
DSA invocationID: 2acaf987-92d4-4379-8bb5-711b168a778d
==== INBOUND NEIGHBORS ======================================
DC=DOMAINNAME,DC=int
VIR\ZENTYAL via RPC
DSA object GUID: c5c1145a-1c62-4728-8652-59912c466118
Last attempt @ 2016-01-11 14:12:19 was successful.
Default-First-Site-Name\SERVER2 via RPC
DSA object GUID: c9696829-4d61-4785-9e97-3526f8023423
Last attempt @ 2016-01-11 14:13:05 was successful.
CN=Configuration,DC=DOMAINNAME,DC=int
Default-First-Site-Name\SERVER2 via RPC
DSA object GUID: c9696829-4d61-4785-9e97-3526f8023423
Last attempt @ 2016-01-11 14:01:10 was successful.
VIR\ZENTYAL via RPC
DSA object GUID: c5c1145a-1c62-4728-8652-59912c466118
Last attempt @ 2016-01-11 14:12:20 was successful.
CN=Schema,CN=Configuration,DC=DOMAINNAME,DC=int
Default-First-Site-Name\SERVER2 via RPC
DSA object GUID: c9696829-4d61-4785-9e97-3526f8023423
Last attempt @ 2016-01-11 13:58:00 was successful.
VIR\ZENTYAL via RPC
DSA object GUID: c5c1145a-1c62-4728-8652-59912c466118
Last attempt @ 2016-01-11 14:12:20 was successful.
DC=DomainDnsZones,DC=DOMAINNAME,DC=int
Default-First-Site-Name\SERVER2 via RPC
DSA object GUID: c9696829-4d61-4785-9e97-3526f8023423
Last attempt @ 2016-01-11 14:11:57 was successful.
VIR\ZENTYAL via RPC
DSA object GUID: c5c1145a-1c62-4728-8652-59912c466118
Last attempt @ 2016-01-11 14:12:20 was successful.
DC=ForestDnsZones,DC=DOMAINNAME,DC=int
Default-First-Site-Name\SERVER2 via RPC
DSA object GUID: c9696829-4d61-4785-9e97-3526f8023423
Last attempt @ 2016-01-11 13:58:00 was successful.
VIR\ZENTYAL via RPC
DSA object GUID: c5c1145a-1c62-4728-8652-59912c466118
Last attempt @ 2016-01-11 14:12:21 was successful.
DsReplicaGetInfo() failed with status 8453 (0x2105):
Replication access was denied.
DsReplicaGetInfo() failed with status 8453 (0x2105):
Replication access was denied.
And this is what samba-tool drs showrepl looks like on the Zentyal DC
ldb_wrap open of secrets.ldb
GENSEC backend 'gssapi_spnego' registered
GENSEC backend 'gssapi_krb5' registered
GENSEC backend 'gssapi_krb5_sasl' registered
GENSEC backend 'spnego' registered
GENSEC backend 'schannel' registered
GENSEC backend 'naclrpc_as_system' registered
GENSEC backend 'sasl-EXTERNAL' registered
GENSEC backend 'ntlmssp' registered
GENSEC backend 'http_basic' registered
GENSEC backend 'http_ntlm' registered
GENSEC backend 'krb5' registered
GENSEC backend 'fake_gssapi_krb5' registered
Using binding ncacn_ip_tcp:Zentyal.DOMAINNAME.int[,seal]
resolve_lmhosts: Attempting lmhosts lookup for name Zentyal.DOMAINNAME.int<0x20>
resolve_lmhosts: Attempting lmhosts lookup for name Zentyal.DOMAINNAME.int<0x20>
resolve_lmhosts: Attempting lmhosts lookup for name Zentyal.DOMAINNAME.int<0x20>
Virden\Zentyal
DSA Options: 0x00000001
DSA object GUID: c5c1145a-1c62-4728-8652-59912c466118
DSA invocationId: f83562bb-716b-49d4-80c2-a1e6e53fb42b
==== INBOUND NEIGHBORS ====
CN=Configuration,DC=DOMAINNAME,DC=int
Default-First-Site-Name\SERVER1 via RPC
DSA object GUID: 2f9f90df-33e0-445a-857a-6f0d34427e51
Last attempt @ Mon Jan 11 15:10:45 2016 CST was successful
0 consecutive failure(s).
Last success @ Mon Jan 11 15:10:45 2016 CST
CN=Configuration,DC=DOMAINNAME,DC=int
Default-First-Site-Name\SERVER2 via RPC
DSA object GUID: c9696829-4d61-4785-9e97-3526f8023423
Last attempt @ Mon Jan 11 15:10:46 2016 CST was successful
0 consecutive failure(s).
Last success @ Mon Jan 11 15:10:46 2016 CST
DC=DOMAINNAME,DC=int
Default-First-Site-Name\SERVER1 via RPC
DSA object GUID: 2f9f90df-33e0-445a-857a-6f0d34427e51
Last attempt @ Mon Jan 11 15:11:47 2016 CST was successful
0 consecutive failure(s).
Last success @ Mon Jan 11 15:11:47 2016 CST
DC=DOMAINNAME,DC=int
Default-First-Site-Name\SERVER2 via RPC
DSA object GUID: c9696829-4d61-4785-9e97-3526f8023423
Last attempt @ Mon Jan 11 15:11:46 2016 CST was successful
0 consecutive failure(s).
Last success @ Mon Jan 11 15:11:46 2016 CST
CN=Schema,CN=Configuration,DC=DOMAINNAME,DC=int
Default-First-Site-Name\SERVER1 via RPC
DSA object GUID: 2f9f90df-33e0-445a-857a-6f0d34427e51
Last attempt @ Mon Jan 11 15:10:50 2016 CST was successful
0 consecutive failure(s).
Last success @ Mon Jan 11 15:10:50 2016 CST
CN=Schema,CN=Configuration,DC=DOMAINNAME,DC=int
Default-First-Site-Name\SERVER2 via RPC
DSA object GUID: c9696829-4d61-4785-9e97-3526f8023423
Last attempt @ Mon Jan 11 15:10:51 2016 CST was successful
0 consecutive failure(s).
Last success @ Mon Jan 11 15:10:51 2016 CST
DC=ForestDnsZones,DC=DOMAINNAME,DC=int
Default-First-Site-Name\SERVER1 via RPC
DSA object GUID: 2f9f90df-33e0-445a-857a-6f0d34427e51
Last attempt @ Mon Jan 11 15:10:41 2016 CST was successful
0 consecutive failure(s).
Last success @ Mon Jan 11 15:10:41 2016 CST
DC=ForestDnsZones,DC=DOMAINNAME,DC=int
Default-First-Site-Name\SERVER2 via RPC
DSA object GUID: c9696829-4d61-4785-9e97-3526f8023423
Last attempt @ Mon Jan 11 15:10:42 2016 CST was successful
0 consecutive failure(s).
Last success @ Mon Jan 11 15:10:42 2016 CST
DC=DomainDnsZones,DC=DOMAINNAME,DC=int
Default-First-Site-Name\SERVER1 via RPC
DSA object GUID: 2f9f90df-33e0-445a-857a-6f0d34427e51
Last attempt @ Mon Jan 11 15:11:37 2016 CST was successful
0 consecutive failure(s).
Last success @ Mon Jan 11 15:11:37 2016 CST
DC=DomainDnsZones,DC=DOMAINNAME,DC=int
Default-First-Site-Name\SERVER2 via RPC
DSA object GUID: c9696829-4d61-4785-9e97-3526f8023423
Last attempt @ Mon Jan 11 15:11:56 2016 CST was successful
0 consecutive failure(s).
Last success @ Mon Jan 11 15:11:56 2016 CST
==== OUTBOUND NEIGHBORS ====
==== KCC CONNECTION OBJECTS ====
Connection --
Connection name: add70383-5836-44b2-bb2b-fb0cfa8f0b0b
Enabled : TRUE
Server DNS name : SERVER1.DOMAINNAME.int
Server DN name : CN=NTDS Settings,CN=SERVER1,CN=Servers,CN=Default-First-Site-Name,CN=Sites,CN=Configuration,DC=DOMAINNAME,DC=int
TransportType: RPC
options: 0x00000001
Warning: No NC replicated for Connection!
Connection --
Connection name: 4e514f64-52b7-434b-ad26-44a02daf2939
Enabled : TRUE
Server DNS name : SERVER2.DOMAINNAME.int
Server DN name : CN=NTDS Settings,CN=SERVER2,CN=Servers,CN=Default-First-Site-Name,CN=Sites,CN=Configuration,DC=DOMAINNAME,DC=int
TransportType: RPC
options: 0x00000001
Warning: No NC replicated for Connection!