Exchange 2016 File Share Witness fails to create directory

Question

_{Friday, October 4, 2019 2:07 PM}

Hi

I have a DAG configured between two Exchange 2016 servers.  It is working well and DB copies are replicating without issue.  The problem is with the File Share Witness directory.  The FSW server is located in a 3rd site.  When I edited the DAG details in EAC and try to set a FSW Directory i get the following errors in one window:

Unable to change the quorum for Database Availability group DAG01.  Witness server \FSW01.contoso.com\DAG01.contoso.com' network name was not found.  This may be due to a firewall setting.

Failed to create file share witness directory C:\Witness on witness server 'FSW01.contoso.com' until this problem is corrected, the DAG may be more vulnerable to failure

No new directory is created on the FSW server.  any pointers would be great.  

All replies (3)

_{Monday, October 7, 2019 9:08 AM ✅Answered}

Thanks for both your responses.  I tried pre-staging as in Edwards suggestion and I also had Exchange Trusted Subsystem added but to no avail.

The issue turns out to be a firewall issue.  It was difficult to narrow them down but ports required appear to be:

TCP Ports

445

135

49152 to 65535

_{Friday, October 4, 2019 6:09 PM | 1 vote}

Hi

I am still old school :-), i like to create the share up front and give permission to the exchange trusted subsystem as i have seen this before often.

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_{Monday, October 7, 2019 7:51 AM | 1 vote}

Hi,

Based on the error info, please try the following steps to troubleshooting:

1.Add the Exchange Trusted Subsystem group to the local Administrators group on the file share witness server.

2.Run the Set-DatabaseAvailabilityGroup command again.

Set-DatabaseAvailabilityGroup <dag name> -WitnessServer <server name> -WitnessDirectory <directory>

Regards,

Kelvin Deng

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