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    Alibaba Cloud DNS:Manage PTR records

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    Alibaba Cloud DNS:Manage PTR records

    Last Updated:Nov 30, 2025

    This topic describes how to configure and manage Pointer (PTR) records for Reverse DNS lookups.

    Prerequisites

    Before you begin, ensure the following requirements are met:

    • Supported IP resources: PTR records can only be configured for Elastic IP Addresses (EIPs) and static public IP addresses of Elastic Compute Service (ECS) instances that belong to your Alibaba Cloud account.

    • Supported IP version: Only IPv4 addresses are supported.

    Add a PTR record

    1. Go to Alibaba Cloud DNS - Reverse DNS Lookup.

    2. Click Add PTR Record.

      image

    3. Enter the required information in the dialog box and click OK.

      Paremeter

      Description

      Public IP region

      Select the region where your public IP resource resides.

      Note

      The system validates that the specified IP address belongs to your Alibaba Cloud account in the selected region. You cannot add a PTR record if verification fails.

      Public IP (EIP or a static IP)

      Enter the public IPv4 address for which you want to configure reverse DNS lookup. Each IP address supports only one PTR record.

      PTR record name

      Automatically generated.

      The system generates this name in the standard in-addr.arpa reverse DNS format. For example, if the IP is 1.2.3.4, the record name is 4.3.2.1.in-addr.arpa.

      TTL

      The Time-To-Live (TTL) value that determines how long DNS records are cached by Local DNS servers. Default: 10 minutes. Recommendation: Set the TTL to match the TTL of the corresponding A record in your authoritative DNS zone. For more information, see How to configure TTL.

      Valid values: 1 second to 24 hours.

      Record Values

      Specify the destination domain name and verify domain ownership.

      1. Enter the destination domain name to which the IP address maps (e.g., example.com). Wildcards are not supported..

      2. Click Verify TXT Record.

        image

      3. In the dialog box that appears, copy the generated Host Record (such as alidnsptrcheck) and Record Value.image

      4. Log on to your DNS provider and add a TXT record to your domain (e.g., example.com) using the copied Host Record and Record Value.

      5. Return to Alibaba Cloud DNS console and click Verify on the Registrant Verification dialog box. You can proceed once verification is successful.

      Note

      For mail servers, ensure the domain name maps to a unique, canonical hostname to improve email deliverability and credibility.

      image

    Modify a PTR record

    You can modify the TTL and Record Values of an existing PTR record.

    1. Go to Alibaba Cloud DNS - Reverse DNS Lookup.

    2. Find the target record and click Edit in the Actions column.

      image

    3. Modify the configuration and click OK.

      Note

      Local DNS servers cache records based on the TTL. Modifications or deletions do not take effect immediately; they apply only after the cached records on Local DNS servers expire. Local DNS servers cache records based on their TTL. For example, if the existing TTL is 10 minutes and you update the record with a new TTL of 1 second, you may still need to wait up to 10 minutes for the change to propagate. The new record and TTL take effect only after the original cache on Local DNS servers expires and triggers a new query to Alibaba Cloud DNS.

      Optimization Tip: To apply changes faster, lower the TTL to a small value and wait for the old TTL to expire before modifying the record content.

    Disable or delete a PTR record

    You can disable or delete a PTR record when it is no longer needed. A disabled or deleted PTR record typically becomes invalid within its TTL period. This process does not exceed 24 hours.

    Important

    In addition to manual deletion, the system performs regular checks on IP ownership. If an IP no longer belongs to your account, the system automatically revokes the associated PTR record. For more information, see PTR record revocation mechanism.

    • Go to Alibaba Cloud DNS - Reverse DNS Lookup.

    • Find the target record, and perform the following operations:

      • Disable the record: Click the toggle switch in the Status column.

        image

        Important

        Disabled records stop resolving but continue to incur charges.

      • Delete the record: You can permanently delete the record to stop incurring charges.

        • In the Actions column for the target record, click Delete.

          image

        • In the dialog box that appears, click OK.

    FAQ

    What do I do if the TXT authorization verification fails?

    Troubleshoot the issue as follows:

    1. Vefiry configuration: Ensure the host record and record value of the TXT record added at your DNS provider match the values provided in the Alibaba Cloud DNS console exactly.

    2. Wait for Propagation: DNS records take time to propagate globally depending on your provider's TTL settings. Wait a few minutes and click Verify again.

    3. Check with Tools: Use a command-line tool like dig or nslookup to verify the record is active. Example: Run dig TXT alidnsptrcheck.<yourdomain>.com and ensure the output matches the required Record Value.

    Why do I receive the error "PTR IP information does not match" or "The current IP may no longer belong to the current user"?

    This feature only supports EIPs and static public IP addresses of ECS instances that belong to your currently logged-in Alibaba Cloud account. Public IP addresses of Simple Application Server (SAS) instances are not supported. IP addresses belonging to other Alibaba Cloud accounts are not supported.