NFC connectivity troubleshooting steps

KB ID: 1198
Product: Veeam Backup & Replication
Version: All
Last Modified: 2018-11-12
KB Languages: DE | ES | FR | IT


A job fails with an error related to NFC connectivity. For example:
“…Client error: NFC storage connection is unavailable…Failed to create NFC download stream.”

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The cause of the majority of NFC errors fall in to 3 primary categories:

• Port (902)
• Permissions*
*If the account that Veeam Backup & Replication is using to communicate with the VMware Environment has granular permissions set please confirm all permissions are set according to the Granular Permissions Guide.
There is also the potential that the issue lies within the VMware Infrastructure itself.


It is suggested that while attempting to resolve this issue the job be configured to use a single proxy. This is done to isolate an issue specific to a single proxy, as well as make it easier to identify which logs are needed.
Port, Permission, or DNS: Investigation
To investigate the potential of a Ports, Permissions, or DNS issue you will need to review the Agent logs.
1.  Navigate to the following location, on the Veeam Proxy


2.  Open the folder that matches the name of the job that is having an issue.
3.  Within this folder you will need to find the agent log for the specific VM.

For a Backup Job:
For a Replication Job:

4.  Search for the following:

Creating NFC download stream

5.  Here you will want to look for the following items that could point to the cause of the error.

a.       Port
If there is an issue with ports, there will be an error after the following:
nfc|           Establishing connection with the host [esx1]. Port: [902]. Failed.
b.      Permissions
If there is an issue with permissions, there will be an error after the following:
nfc|           Sending authd message: [SESSION ID NUMBER].
nfc|           Sending authd message: [Name of Host].
nfc|           Waiting for the authd reply message...
c.       DNS
If there is an issue with DNS, the following error will be found.
nfc|             Resolving host name (esx1) to IP address...
nfc|             Resolving host name (esx1) to IP address... Failed.

NFC Connectivity Troubleshooting

The Management Agents for that host may need to be restarted.

More Information

The proxy being used to process a VM can be identified by opening the “Task” log specific to the VM from inside the folder named after the job in %programdata%\Veeam\Backup. Searching the Task log for the words “starting agent” will allow for the identification of which server performed the task.
Further information can be found in this forum post:
The NFC connection requires the following:
  • DNS Resolution of target host
  • Port 902 is open to/from Backup Server/Proxy to ESX(i) host
  • Permissions to download files via ESX(i) host and/or vCenter
An issue with Port 902 may represent an issue with a firewall on the ESXi host, Veeam Proxy, or the connection between the two.


Please be aware that we’re making changes which will restrict access to product updates for users without an active contract.


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