AB#4464 error-0xa8b-resolve-dns-fail

Author: v-lianna

support/windows-server/active-directory/error-0xa8b-resolve-dns-fail .md

@@ -0,0 +1,72 @@
+---
+title: An Attempt to Resolve the DNS Name of a DC in the Domain Being Joined Has Failed
+description: Provides troubleshooting steps for resolving the Domain Name System (DNS) error code 0xa8b when you join a workgroup computer to a domain.
+ms.date: 03/19/2025
+manager: dcscontentpm
+audience: itpro
+ms.topic: troubleshooting
+ms.reviewer: kaushika, raviks, v-lianna
+ms.custom:
+- sap:active directory\on-premises active directory domain join
+- pcy:WinComm Directory Services
+---
+# Error code 0xa8b: An attempt to resolve the DNS name of a DC in the domain being joined has failed
+
+This article provides troubleshooting steps for resolving the Domain Name System (DNS) error code 0xa8b when you join a workgroup computer to a domain. It includes causes and resolutions for common DNS issues.
+
+When you join a workgroup computer to a domain, you receive the following error message:
+
+> An attempt to resolve the DNS name of a DC in the domain being joined has failed. Please verify this client is configured to reach a DNS server that can resolve DNS names in the target domain.
+
+When you check the **NetSetup.log** file, you see the following entries:
+
+```output
+mm/dd/yyyy hh:mm:ss:ms NetpDsGetDcName: status of verifying DNS A record name resolution for '<DC name>.<domain>.<tld>: 0x2746
+mm/dd/yyyy hh:mm:ss:ms NetpDsGetDcName: failed to find a DC in the specified domain: 0xa8b, last error is 0x0
+mm/dd/yyyy hh:mm:ss:ms NetpJoinDomainOnDs: NetpDsGetDcName returned: 0xa8b
+mm/dd/yyyy hh:mm:ss:ms NetpJoinDomainOnDs: Function exits with status of: 0xa8b
+mm/dd/yyyy hh:mm:ss:ms NetpDoDomainJoin: status: 0xa8b
+```
+
+Here's more information about the error code:
+
+|HEX error  |Decimal error  |Symbolic error string  |
+|---------|---------|---------|
+|0xa8b     |2699         |NERR_SetupCheckDNSConfig         |
+
+This error occurs for one or more of the following reasons:
+
+- The workgroup computer being joined points to an invalid DNS server.
+- The DNS server(s) used by the joining computer is invalid, is missing the required zones, or is missing the required records for the target domain.
+- The target Active Directory domain contains a problematic DNS name.
+- Network problems exist on either the workgroup computer, the target domain controller (DC), or the network used to connect the client and target DC.
+
+## Troubleshooting steps
+
+To resolve this error, follow these steps:
+
+1. Verify that the computer being joined points to valid DNS server IP addresses. Invalid examples include:
+
+    - Invalid Internet Service Provider (ISP)-provided DNS servers.
+    - A stale or non-existent DNS server on the corporate intranet.
+    - A DNS server in an error state that prevents it from loading the `_msdcs.<forest root domain>` or target AD domain zones, or from resolving queries for those zones. Event ID 4521 might be logged.
+
+2. Verify that all DNS servers configured on the client host the required zones and valid records for a DC in the target domain. Check for the following misconfigurations:
+
+    - Forward lookup zone for the target AD domain is missing.
+    - The `_msdcs` forward lookup zone is missing.
+    - The `_msdcs.<forest root domain>` zone doesn't contain a Lightweight Directory Access Protocol (LDAP) SRV record for a DC in the target domain.
+    - Host A record is missing from the target AD domain zone.
+    - Host A record is present but contains the wrong IP address for the target DC.
+    - The host A record is present but was registered by a network interface that isn't accessible to the client computer.
+
+3. Check for special names in the target Active Directory domain that require additional configuration:
+
+    - Single-label DNS name.
+    - Disjoint namespace.
+    - All numeric top-level domains (TLDs) or TLDs containing numeric characters.
+
+4. Check for network problems on the workgroup computer, target DC, or the network connecting the computer and the target DC:
+
+    - A broken Network Interface Card (NIC)  on the client computer or the target DC.
+    - A broken network link.

support/windows-server/toc.yml

@@ -357,6 +357,8 @@ items:
       href: ./active-directory/cannot-connect-internet-domain.md
     - name: Default limit to workstation numbers
       href: ./active-directory/default-workstation-numbers-join-domain.md
+    - name: Error code 0xa8b
+      href: ./active-directory/error-0xa8b-resolve-dns-fail.md      
     - name: Netlogon service doesn't keep settings after in-place upgrade
       href: ./active-directory/netlogon-service-not-start-automatically.md
     - name: Support boundaries for Active Directory over NAT