|
| 1 | +--- |
| 2 | +title: An Attempt to Resolve the DNS Name of a DC in the Domain Being Joined Has Failed |
| 3 | +description: Provides troubleshooting steps for resolving the Domain Name System (DNS) error code 0xa8b when you join a workgroup computer to a domain. |
| 4 | +ms.date: 03/26/2025 |
| 5 | +manager: dcscontentpm |
| 6 | +audience: itpro |
| 7 | +ms.topic: troubleshooting |
| 8 | +ms.reviewer: kaushika, raviks, herbertm, dennhu, eriw, v-lianna |
| 9 | +ms.custom: |
| 10 | +- sap:active directory\on-premises active directory domain join |
| 11 | +- pcy:WinComm Directory Services |
| 12 | +--- |
| 13 | +# Error code 0xa8b: An attempt to resolve the DNS name of a DC in the domain being joined has failed |
| 14 | + |
| 15 | +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. |
| 16 | + |
| 17 | +When you join a workgroup computer to a domain, you receive the following error message: |
| 18 | + |
| 19 | +> 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. |
| 20 | +
|
| 21 | +When you check the **NetSetup.log** file, you see the following entries: |
| 22 | + |
| 23 | +```output |
| 24 | +NetpDsGetDcName: status of verifying DNS A record name resolution for '<DC name>.<domain>.<tld>: 0x2746 |
| 25 | +NetpDsGetDcName: failed to find a DC in the specified domain: 0xa8b, last error is 0x0 |
| 26 | +NetpJoinDomainOnDs: NetpDsGetDcName returned: 0xa8b |
| 27 | +NetpJoinDomainOnDs: Function exits with status of: 0xa8b |
| 28 | +NetpDoDomainJoin: status: 0xa8b |
| 29 | +``` |
| 30 | + |
| 31 | +Here's more information about the error code: |
| 32 | + |
| 33 | +|HEX error |Decimal error |Symbolic error string | |
| 34 | +|---------|---------|---------| |
| 35 | +|0xa8b |2699 |NERR_SetupCheckDNSConfig | |
| 36 | + |
| 37 | +This error occurs for one or more of the following reasons: |
| 38 | + |
| 39 | +- The workgroup computer being joined points to an invalid DNS server. |
| 40 | +- The DNS server used by the joining computer is invalid, is missing the required zones, or is missing the required records for the target domain. |
| 41 | +- The target Active Directory (AD) domain contains a problematic DNS name. |
| 42 | +- Network problems exist on the workgroup computer, the target domain controller (DC), or the network used to connect the client and target DC. |
| 43 | + |
| 44 | +## Troubleshooting steps |
| 45 | + |
| 46 | +To resolve this error, follow these steps: |
| 47 | + |
| 48 | +1. Verify that the computer being joined points to valid DNS server IP addresses. Invalid examples include: |
| 49 | + |
| 50 | + - Invalid Internet Service Provider (ISP)-provided DNS servers. |
| 51 | + - ISP-provided DNS servers that don't host the AD domain zone. |
| 52 | + - A stale or nonexistent DNS server on the corporate intranet. |
| 53 | + - A corporate network DNS server that doesn't host the AD domain zone. |
| 54 | + - A corporate network 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. |
| 55 | + |
| 56 | +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: |
| 57 | + |
| 58 | + - Forward lookup zone for the target AD domain is missing. |
| 59 | + - The `_msdcs` forward lookup zone is missing. |
| 60 | + - The `_msdcs.<forest root domain>` zone doesn't contain a Lightweight Directory Access Protocol (LDAP) SRV record for a DC in the target domain. |
| 61 | + - The host A record is missing from the target AD domain zone. |
| 62 | + - The host A record is present but contains the wrong IP address for the target DC. |
| 63 | + - The host A record is present but is registered by a network interface that isn't accessible to the client computer. |
| 64 | + |
| 65 | +3. Check for special names in the target Active Directory domain that require other configuration: |
| 66 | + |
| 67 | + - Single-label DNS name. For more information, see [Deployment and operation of Active Directory domains that are configured by using single-label DNS names](deployment-operation-ad-domains.md#how-to-enable-windows-based-clients-to-do-queries-and-dynamic-updates-with-single-label-dns-zones). |
| 68 | + - Disjoint namespace. For more information, see [Event IDs 5788 and 5789 occur on a Windows-based computer](event-ids-5788-5789.md). |
| 69 | + - All numeric top-level domains (TLDs) or TLDs containing numeric characters. |
| 70 | + |
| 71 | +4. Check for network problems on the workgroup computer, target DC, or the network connecting the computer and the target DC: |
| 72 | + |
| 73 | + - A broken Network Interface Card (NIC) on the client computer or the target DC. |
| 74 | + - A broken network link. |
| 75 | + |
| 76 | +You can use tools like [nslookup](/windows-server/administration/windows-commands/nslookup) to verify the availability and content of DNS records from the client end, and use tools like [ping](/windows-server/administration/windows-commands/ping) or [tracert](/windows-server/administration/windows-commands/tracert) to check the reachability of IP addresses. You can use [PortQry](../networking/portqry-command-line-port-scanner-v2.md) to try specific DC UDP and TCP server ports. A starting point for DC server ports is to [Configure a firewall for AD domains and trusts](config-firewall-for-ad-domains-and-trusts.md). |
0 commit comments