# Preparing DNS for Commvault Grid Deployment

Commvault Grid uses DNS to communicate with the CommServe server, clients, and other infrastructure components. Proper DNS configuration is required for both deployment and ongoing operations. DNS misconfiguration is one of the most common causes of deployment and communication issues.

Configure and validate all required DNS records before deploying Commvault Grid nodes.

## DNS Requirements

The following DNS requirements apply to Commvault Grid deployments:

- DNS records are required for the data protection network interfaces on all Commvault Grid nodes.

- DNS records are required for the optional management network interfaces, if a management network is used.

- DNS records are not required for storage pool network interfaces.

- Configure DNS records on multiple redundant DNS servers whenever possible to improve resiliency.

- DNS records must exist before deployment and remain available throughout the lifecycle of the cluster.

- Both forward (A) and reverse (PTR) DNS records are required.

Note

DNS records are required only for the data protection network and optional management network.

The storage pool network does not require DNS records.

## DNS Naming Requirements

All DNS records must use Fully Qualified Domain Names (FQDNs).

Examples:

- Valid: HSA1.domain.com
- Invalid: HSA1

Note

A DNS server is required.

Hosts file entries cannot be used as an alternative to DNS.

## DNS Server Recommendations

For improved resiliency and availability:

- Configure redundant DNS servers.
- Ensure all Commvault Grid nodes can reach the DNS servers.
- Verify both forward and reverse DNS resolution.
- Use DNS infrastructure that is highly available and regularly backed up.

Note

If your DNS server is configured for non-secure DNS updates (not recommended by Microsoft), disable this configuration before deploying Commvault Grid.

## Required DNS Records

Create the following DNS records for every Commvault Grid node:

- Forward DNS records (A records)
- Reverse DNS records (PTR records)

DNS records are required for:

- Data protection network interfaces
- Optional management network interfaces

DNS records are not required for:

- Storage pool network interfaces

## Verifying DNS Records

Verify and validate the DNS records associated with all Commvault Grid nodes before deployment.

The DNS records can be validated from any computer that has access to the DNS server.

### Verifying Forward Records (A Records)

Use the following command to verify A records:

    nslookup $[node_fqdn]

Example:

    nslookup HSA1.domain.com
    Server:           172.16.10.11
    Address:          172.16.10.11#53
    Name:     HSA1.domain.com
    Address:  172.16.10.101

## Verifying Reverse Records PTRRecords

Use the following command to verify PTR records:

    nslookup $[node_IP_addr]

Example:

    nslookup 172.16.10.101
    Server:           172.16.10.11
    Address:          172.16.10.11#53
    101.10.16.273.in-addr.arpa      name =HSA1.domain.com

## DNS Validation Checklist

Before deploying Commvault Grid nodes, verify the following:

- Forward DNS records Arecords exist for all nodes.
- Reverse DNS records PTRrecords exist for all nodes.
- FQDNs resolve correctly.
- Reverse lookups resolve correctly.
- DNS servers are reachable from all Commvault Grid nodes.
- Redundant DNS servers are configured.
- Data protection network interfaces have DNS records.
- Management network interfaces have DNS records ifused.
- Storage pool interfaces do not have DNS records.

## Common DNS Issues

The following DNS issues commonly cause deployment failures:

- Missing forward DNS records
- Missing reverse DNS records
- Incorrect IP address mappings
- Use of short host names instead of FQDNs
- DNS records created only on a subset of DNS servers
- Use of hosts file entries instead of DNS
- Unreachable DNS servers

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