TCP Timeout Issues in Azure

Question

TCP Timeout Issues in Azure

Brad Farmer 20

I'm running into an issue with TCP timeouts and Helix(Perforce) Core on a fairly new Azure Instance. With large file uploads we keep seeing TCP resets. The application is set to defer to the OS. Everything on the OS appears to be at the default settings with TCP. No matter what options we tweak, we can't seem to go longer than 4 minutes without a TCP reset.

We are not running Azure Firewall or a Load Balancer, which is where nearly all the documentation points for this type of issue. I did find one lone article talking about a 4 minute timeout for an FTP server in Azure. They mentioned the only way to fix it was to use a command called set-azureendpoint to modify the TCP properties on the AzureVM using powershell. I've had trouble getting this command to work but before I dive too deep into this rabbit hole is there any light anyone can shed on this?

PS. We run a Fortigate in Azure. The settings there for TCP are fairly loose by default.

Vamsi Ram Annepu 640 Reputation points Microsoft External Staff

2025-04-07T21:00:34.42+00:00

Hi Brad Farmer,
Can you give us more information to help you.
Which azure instance (VM or VMSS) are you using and the configuration of it, and the default OS settings information, Fortigate appliance configuration
Vamsi Ram Annepu 640 Reputation points Microsoft External Staff

2025-04-07T21:07:42.12+00:00

Repeated
Rohith Vinnakota 4,345 Reputation points Microsoft External Staff

2025-04-08T19:05:28.12+00:00

Hello @Brad Farmer
Could you please try the following options:

Adjust TCP/IP Settings:

   - For Windows:

     - Open the Registry Editor and navigate to HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters.

     - Modify the desired TCP parameters, such as TcpMaxDataRetransmissions or TcpWindowSize.

Additionally,

Consider enabling Accelerated Networking for your VM to reduce latency and improve throughput. Also, change the idle timeout value on the public IP address associated with the VM if the connection occurs via the VM's public IP.

Reference link: https://stackoverflow.com/questions/33692173/azure-vm-tcp-idle-timeout

Kindly let us know if the above helps or you need further assistance on this issue.
Rohith Vinnakota 4,345 Reputation points Microsoft External Staff

2025-04-10T00:45:39.4666667+00:00

Hello @Brad Farmer

Following up to see if the above suggestion was helpful. And, if you have any further query do let us know.
Rohith Vinnakota 4,345 Reputation points Microsoft External Staff

2025-04-10T18:55:47.1266667+00:00

Hello @Brad Farmer

Following up to see if the above suggestion was helpful. And, if you have any further query do let us know.

Accepted answer

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Vamsi Ram Annepu 640 Reputation points Microsoft External Staff

2025-04-07T21:00:34.42+00:00

Hi Brad Farmer,
Can you give us more information to help you.
Which azure instance (VM or VMSS) are you using and the configuration of it, and the default OS settings information, Fortigate appliance configuration
Vamsi Ram Annepu 640 Reputation points Microsoft External Staff

2025-04-07T21:07:42.12+00:00

Repeated
Rohith Vinnakota 4,345 Reputation points Microsoft External Staff

2025-04-08T19:05:28.12+00:00

Hello @Brad Farmer
Could you please try the following options:

Adjust TCP/IP Settings:

- For Windows:

- Open the Registry Editor and navigate to HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters.

- Modify the desired TCP parameters, such as TcpMaxDataRetransmissions or TcpWindowSize.

Additionally,

Consider enabling Accelerated Networking for your VM to reduce latency and improve throughput. Also, change the idle timeout value on the public IP address associated with the VM if the connection occurs via the VM's public IP.

Reference link: https://stackoverflow.com/questions/33692173/azure-vm-tcp-idle-timeout

Kindly let us know if the above helps or you need further assistance on this issue.
Rohith Vinnakota 4,345 Reputation points Microsoft External Staff

2025-04-10T00:45:39.4666667+00:00

Hello @Brad Farmer

Following up to see if the above suggestion was helpful. And, if you have any further query do let us know.
Rohith Vinnakota 4,345 Reputation points Microsoft External Staff

2025-04-10T18:55:47.1266667+00:00

Hello @Brad Farmer

Following up to see if the above suggestion was helpful. And, if you have any further query do let us know.

Answer 1

Hello @Brad Farmer ,

Welcome to the Microsoft Q&A Platform. Thank you for reaching out & I hope you are doing well.

Helix(Perforce) Core are SAAS offering from Perforce and hence the instance settings are managed by the SAAS provider on Azure Marketplace.
Hence Perforce support team need to be engaged to advise the settings on the Helix instance
I found once article which talks about setting up the keepalives to maintain TCP settings on Helix instance and on client side. Refer the below article.
https://portal.perforce.com/s/article/net-keepalive-settings-don-t-always-work-with-parallel-syncs-in-Helix-Core
Since you already mentioned that you are not running Azure Firewall or a Load Balancer or other transit device, it seems you need to tune TCP settings on instance itself.
set-azureendpoint command is long deprecated and was useful for configuring endpoints and ACLs(Replaced by NSG), it does not directly modify TCP settings. The cmdlet was part of the Azure Service Management (ASM) model (aka "classic" deployment model), which has largely been replaced by Azure Resource Manager (ARM).

Hope the answer is able to help to reach the right support.

If the below answer addressed your query, please don’t forget to click "Accept the answer" and Up-Vote for the same, which might be beneficial to other community members reading this thread. And, if you have any further query do let us know.

Thanks,

Ujjawal Tyagi

UJTyagi-MSFT 930 Reputation points Microsoft Employee

2025-04-11T02:38:17.77+00:00

Hello @Brad Farmer ,

Kindly let me if you have any further queries

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TCP Timeout Issues in Azure

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