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Rescan fails with "Unable to install backup agent: cannot connect to Error: Known agent have the same bios uuid but different connection point ."

KB ID: 4205
Product: Veeam Agent for Microsoft Windows | 2.2 | 3.0.2 | 4.0 | 5.0 | 6.0 | 6.1
Published: 2021-09-10
Last Modified: 2024-04-18
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Scenario Specific Article

This article documents the solution for specific scenarios.

If the scenarios listed in the Cause section do not match your situation, please create a support case.

Challenge

During the rescan of a Protection Group, the following error occurs:

Unable to install backup agent: cannot connect to <machine> Error:

followed by either:

  • Known agent <hostname> have the same bios uuid <uuid_value> but different connection point <different_ip>.
    
    or
  • Failed to call RPC function 'EpAgentCollectSystemInfo' : Machine doesn't have identifiers.
    
Veeam Backup & Replication Configuration Cause

This article primarily focuses on environmental causes that can lead to this error. However, there is one possible cause that can be attributed to a configuration issue:

Attempting to add a machine to any protection group when it already exists in a protection group may cause this issue. Machines may be added to a protection group using either their hostname, FQDN, or IP. It is possible, but not recommended, to add a machine to multiple protection groups, but it must be done using the same identification method (i.e., hostname, FQDN, or IP). For example, the error will occur if a machine is initially added to a protection group using its FQDN and is later added to the same protection group or any other protection group using the hostname or IP address.

Another example of when this conflict might occur is if a machine was initially added to a backup job using the 'Individual Computer' option, which would result in it being added to the 'Manually Added' protection group. The conflict arises when a protection group is later created using a different identification method (i.e., hostname, FQDN, or IP). During the rescan of that protection group, the machine addition would fail, triggering this error.

Cause

Scenario 1: Reinstalled OS

The OS was reinstalled on the machine that is displaying this error during rescan.

Scenario 2: Different Machines, Same BIOS UUID

An entirely different machine has been added to the Protection Group. However, those machines have the same BIOS UUID.

The UUID value of a machine can be checked using the following PowerShell cmdlet:

(Get-WmiObject Win32_ComputerSystemProduct).UUID

Scenario 3: Environment with frequent DHCP IP changes

The workstations connect to the network using a VPN solution that assigns a different IP address after each connection, leading to a situation where the cached DNS information stored by the Windows OS of the Veeam Backup & Replication server is out of date.

Scenario 4: Machine BIOS UUID is NULL

The BIOS UUID of a machine is reported as NULL or "zeroed out." This situation may also be accompanied by an error reporting:

Machine doesn't have identifiers.

The UUID value of a machine can be checked using the following PowerShell cmdlet:

(Get-WmiObject Win32_ComputerSystemProduct).UUID

Solution

Scenario 1: Reinstalled OS

To resolve the conflict, remove the old machine's entry from the Protection Group.

Scenario 2: Different Machines, Same BIOS UUID

Each Veeam Agent computer that consumes a license installed in Veeam Backup & Replication must have a unique BIOS UUID.

  • If different physical machines have the same BIOS UUIDs, contact the hardware vendor to request assistance ensuring each machine has a unique BIOS UUID.
  • If the conflict occurs among virtual machines with the same BIOS UUID, please contact the hypervisor vendor's support team for help modifying the virtual machine BIOS UUIDs.

Scenario 3: Environment with frequent DHCP IP changes

OS Level Change

Please be advised that the solution provided for this scenario is shared as a courtesy. Veeam Support strongly suggests you review this change carefully and understand the effects of implementing such change. This change will affect the quantity of DNS requests sent by the Veeam Backup & Replication server.

As this is an OS Level change, Veeam Support is unable to assist with deployment.

In environments where DNS records are updated frequently, it is advisable to consider configuring DNS Aging and Scavenging settings to remove stale DNS records automatically.

By default, Windows OS caches DNS records for one day. The MaxCacheTtl registry value may be adjusted on the Veeam Backup & Replication server in environments with frequent DNS changes to reduce invalid cached information.

The example below demonstrates how to set the DNS Cache TTL to 1 second, essentially disabling all DNS caching.

Key Location: HKLM\SYSTEM\CurrentControlSet\Services\Dnscache\Parameters\
Value Name: MaxCacheTtl 
Value Type: DWORD (32-Bit) Value
Value Data: 1

PowerShell:

New-ItemProperty -Path 'HKLM:\SYSTEM\CurrentControlSet\Services\Dnscache\Parameters\' -Name MaxCacheTtl -PropertyType DWORD -Value 1

Scenario 4: NULL BIOS UUID or "Machine doesn't have identifiers"

The BIOS UUID of a machine must be unique; a null UUID value is not accepted.

If a machine is found to have a null BIOS UUID, contact the hardware vendor to request assistance in ensuring each machine has a unique BIOS UUID.

More Information

Further discussion regarding Duplicate BIOS UUIDs can be found in our R&D Forums here:  Veeam R&D Forums: Duplicate UUIDs
Limited Support Workaround for Duplicate or NULL BIOS UUIDs
Limited Support

This workaround is functional, and Veeam Support fully supports environments that use it. However, the implementation and configuration of this workaround are outside the scope of Veeam Support. The backup administrator must deploy the workaround, and they must ensure that the UUID manually specified is truly unique in the environment. Veeam Support will not assist with troubleshooting UUID conflicts caused by the misconfiguration of this workaround.

Veeam Support strongly advises resolving the cause of the duplicate or null BIOS UUIDs instead of choosing to use this registry value.

If it is impossible to make the BIOS UUID for a machine unique, the following workaround may be implemented to force Veeam Agent to utilize a user-specified UUID value to identify the machine.

Windows OS

Use the following PowerShell cmdlets on the machine with the duplicate or null BIOS UUID.

Enable UUID Failover:
New-ItemProperty -Path 'HKLM:\SOFTWARE\Veeam' -Name EnableSystemUuidFailover -PropertyType DWORD -Value 1
Configure Custom System UUID Value:

Note: The following command must be modified to replace <UUID> with a user-generated GUID.

New-ItemProperty -Path 'HKLM:\SOFTWARE\Veeam' -Name SystemUuid -PropertyType String -Value '<UUID>'

Linux OS

  1. Stop the veeamservice service.
  2. Delete or rename the existing /var/lib/veeam/veeam_db.sqlite
  3. Generate a random UUID and specify it in /etc/veeamagentid
    The UUID value in the veeamagentid file must be in curly braces.
  4. Start the veeamservice service.
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