Windows Server Active Directory DNS & DHCP Replication Errors
Diagnose and resolve Active Directory replication failures, Event IDs 1311/2042/8614, and DHCP authorization conflicts.
⚡ Direct Answer & Quick Diagnostic Summary (AEO)
To resolve Active Directory replication failures, Directory Service Event IDs 1311/2042/8614, and RPC error 1722, verify the network adapter DNS configuration on all Domain Controllers (DCs). Primary DNS on DC1 must point to DC2's static IP address (e.g., 192.168.1.11) with 127.0.0.1 as secondary DNS; never assign 127.0.0.1 as primary DNS. Open elevated PowerShell and execute "repadmin /syncall /AeDqP" to force multi-master partition synchronization across all naming contexts. Synchronize Kerberos time clocks against the PDC Emulator using "w32tm /config /syncfromflags:DOMHIER /update" followed by "w32tm /resync"; authentication fails if clock skew exceeds 300 seconds. Verify Windows Firewall allows inbound RPC dynamic ports (TCP 49152–65535), Kerberos (UDP/TCP 88), and LDAP (TCP 389). In the DHCP Management console, right-click the root node, select Manage Authorized Servers, authorize the DC, and run "Reconcile All Scopes" to repair lease database corruption.
Primary Root Causes
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Step-by-Step Diagnostic Checklist
Step 1: Audit DNS Configuration on All Domain Controllers
On DC1, set Primary DNS to DC2 IP (e.g. 192.168.1.11) and Secondary to 127.0.0.1. On DC2, set Primary DNS to DC1 IP (192.168.1.10) and Secondary to 127.0.0.1. Never set 127.0.0.1 as primary DNS.
Step 2: Execute Repadmin Replication Health Checks
Open elevated Command Prompt and run "repadmin /replsummary" and "repadmin /showrepl * /csv > repl.csv". Identify specific failing naming contexts and error codes (e.g. Error 1722 RPC Server Unavailable or Error 8453 Access Denied).
Step 3: Force Domain-Wide Active Directory Synchronization
Run "repadmin /syncall /AeDqP" to force immediate multi-master partition synchronization across all organizational units and Schema partitions.
Step 4: Synchronize Domain Hierarchy Time via NTP
Check PDC Emulator clock: run "w32tm /query /status". Synchronize all child DCs to the PDC emulator with "w32tm /config /syncfromflags:DOMHIER /update" followed by "net stop w32time && net start w32time".
Step 5: Verify RPC & Active Directory Inbound Firewall Rules
Ensure Windows Firewall on all DCs allows Inbound rules for Active Directory Domain Controller (RPC, RPC Endpoint Mapper TCP 135, Kerberos UDP/TCP 88, LDAP TCP 389, DNS TCP/UDP 53).
Step 6: Authorize DHCP Server & Reconcile Scopes
Open DHCP MMC, right-click DHCP root and select Manage authorized servers. Authorize your server IP. In each IPv4 Scope, right-click and choose Reconcile All Scopes to repair lease database inconsistencies.
Frequently Asked Questions
What causes Active Directory Error 1722: The RPC server is unavailable?
Error 1722 is almost always caused by DNS misconfiguration, Windows Firewall blocking RPC dynamic ports (TCP 49152-65535), or time skew greater than 5 minutes between domain controllers.
How do I force immediate AD replication between two Windows Servers?
Open PowerShell as Administrator and run: "repadmin /syncall /AdePq" to synchronize all directory partitions across all DCs.
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