I am currently working with a client that requires access to all Azure resource locking down as much as possible and I am having problems with the Storage Account that is utilised by our Azure Functions.
With the Firewalls and Virtual Networks blade in portal set to "All Networks" I am able to deploy to the Function App and it runs without issue.
However once I enable the access restriction by checking "Selected Networks"no matter what virtual network subnets I enter or IP Addresses I can not get the communication to work
I have entered the Outbound IP Addresses of our Consumption based Function App and also check that the additional IP Addresses from the Powershell and all have been added to the whitelist. I have also added all the CIDR IP ranges of the local Azure datacenter but again it does not work.
The problem we have is that once the access restrictions have been put into place we are unable to deploy to the Function App and the app no longer runs. Is this scenario supported and what is the mechanism for tying down access to the Storage Account so that only the Function App can utilise it.
As far as I know, you have two options to restrict access to your storage account from your function app or web app.
Whitelist the outboundIpAddresses and possibleOutboundIpAddresses of the function app in the firewall of the storage account. However, it does not work if the Azure function app and Azure storage located in the same region refer to Sam's answer.
when you hit the storage account from your function, because they are
in the same region as each other, all the traffic goes over the
internal Azure network on internal IP's, not the public IPs listed in
the web app, and so is not allowed over the firewall.
If your resources were in different regions, you could use the network section of function app to allow function app to access resources in a VNet, then enable service endpoint for Microsoft.Storage in this app integration subnet. But you need Azure Functions Premium plan referring to this tutorial: integrate Functions with an Azure virtual network.
Sometimes, the deployment order for networking is important. In this case, you will deploy the followings:
Firstly, you could deploy new VNet integration with an unused subnet. After the VNet Integration is completed and the function app is restarted, you could enable service endpoint for this subnet. In the end, you could add the subnet in the firewall of the storage account.
Note that the new version is in Preview, currently. You could also check these characteristics and get more references from this thread.
Related
I have been using azure timer based function in my project.
Since I started using the function, I was getting error 403 related to access forbidden from Azure storage account.
I tried adding AzureWebJobsStorage Key in function's configuration
I tried adding outbound IPs of Allowed ip ranges of azure storage accounts
I tried checking the option of allowing azure managed services to the storage account.
However, I'm still getting the error in that particular timer function of my function app. The other functions run properly.
Although, if I allow all the networks in storage account firewall and VN settings, my function runs proper.
Both the function and storage account are in same region.
I want to enable it somehow that I do not need to choose the allow all networks. What can be done?
In case anyone else is searching for this... I had a similar issue. I had a function app that I had created a private endpoint and regional VNet integration back with the VNet interacting with a Storage Account that also had a private endpoint with the same VNet. The Storage Account's network/firewall settings only allowed connections from the VNet (no external traffic allowed). Both the storage account and function app reside in the same region.
Attempt at fix #1 (not ideal):
I added code to determine what IP the function app was running from. That led me to add all of the IP's in the portal under function app --> Properties --> Additional Outbound IP Addresses. This is exposed by Terraform if using that.
Attempt at fix #2 (better):
The resolution is to ensure you have the proper function app settings set.
See: Microsoft documentation
Setting
Suggested value
Description
WEBSITE_CONTENTOVERVNET
1
Create this app setting. A value of 1 enables your function app to scale when your storage account is restricted to a virtual network.
WEBSITE_DNS_SERVER
168.63.129.16
Create this app setting. When your app integrates with a virtual network, it will use the same DNS server as the virtual network. Your function app needs this setting so it can work with Azure DNS private zones. It's required when you use private endpoints. This setting and WEBSITE_VNET_ROUTE_ALL will send all outbound calls from your app into your virtual network.
WEBSITE_VNET_ROUTE_ALL
1
Create this app setting. When your app integrates with a virtual network, it uses the same DNS server as the virtual network. Your function app needs this setting so it can work with Azure DNS private zones. It's required when you use private endpoints. This setting and WEBSITE_DNS_SERVER will send all outbound calls from your app into your virtual network.
Note: The 168.63.129.16 is a static value for Azure DNS.
After setting all of these, my function app was able to connect to the storage account through the VNet as expected.
There're already some answers about this issue, you can see here and here.
In short, if the function and storage account are in same region, they communicate in an internal way without going through outboundIpAddresses.
The workaround is that create them in different regions.
What am I trying to achieve
Connect to an Azure BLOB storage account that sits behind a firewall through an Azure Function.
Steps Taken so Far
Azure Function developed and tested against public storage account which works as expected.
Following Azure Resource Explorer for my Azure Function I find out the outbound addresses("outboundIpAddresses" entry) and I add them in the firewall of the storage Account.
Issue
While trying to run the Azure Function against the storage account with the firewall I am getting a Status: 500 Internal Server Error - This request is not authorized to perform this operation.
What am I missing here?
You won't be able to achieve what you want here currently. When you hit the storage account from your funciton, because they are in the same region as each other, all the traffic goes over the internal Azure network on internal IP's, not the public IPs listed in the web app, and so is not allowed over the firewall (I have had this confirmed by Azure support). Because you don't have access to the internal IPs of the function, and even if you did they can change, you can't whitelist them.
If your resources were in different regions, traffic would go over the external IPs and you would have more success.
Originally I tried to restrict access from an app service to blob storage using IP addresses, however it turned out that you can only do this using a Virtual Network: Firewall access from Azure app service to blob storage
I want to be able to achieve this without setting up a point-to-site VPN. The steps I have taken to set up a virtual network in Azure are as follows:
Created Network security group "securitygroup-frontend", add custom
inbound rule called Web with Source: Service Tag, Source service tag:
Internet, Source port ranges: *, Destination : Any, Destination port
ranges: 80, 443, Protocol: Any, Action: Allow, Priority: 100
Created Virtual Network with address space 192.168.0.0/23 and subnet called frontend address range 192.168.0.0/26 with network security group: securitygroup-frontend and subnet delegation to Microsoft.Web/serverFarms and service endpoints Microsoft.Storage
Went to app service -> Networking -> Configure VNet integration ->
Add VNet preview and select the subnet you created
Went to Storage -> Firewalls and virtual Networking -> Configure VNet integration -> Select 'Selected networks' and add in the virtual network and subnet just created.
I have had to move Azure diagnostics and logs such as for key vault, service bus and sql azure to its own blob storage as these require blob storage outside of a virtual network and can't be made to work inside. The app service is in the Standard plan. The app service, blob storage and virtual network are all in the same region.
This question and answer does not provide any insights: https://social.msdn.microsoft.com/Forums/azure/en-US/9f4d8aeb-68a6-4ec1-9e11-bee2d1301792/allow-access-to-azure-storage-account-only-from-an-app-service?forum=windowsazurewebsitespreview
The above steps though block off access from the app service to blob storage and any assets within return an error: (403) Forbidden. If I remove the Virtual network from blob storage it works fine. What am I doing wrong?
Yes, you can do this using a VNet but you need to deploy the web app in a VNet with App Service Environments. You can not do this with VNet integration. Integrating Azure services to an Azure virtual network enables private access to the service from virtual machines or compute resources in the virtual network. However, web app service in a regular app service plan is multi-tenant. With ASE, you could deploy it into your VNet.
You could get more details and explanation from this similar thread. According to a comment from silent, you could also consider deploying your web app inside a container which could be deployed in a VNet with some restriction.
Update
Sometimes, the deployment order for networking is important. In your case, you enable service endpoint before VNet integration. I suggest removing NSG restriction in integrated app subnet VNet for a test. Then you could check the following steps.
Firstly, you could deploy new VNet integration with an unused subnet. After the VNet Integration is completed and the web app is restarted, you could enable service endpoint and subnet delegation for this subnet. In the end, you could add the subnet in the firewall of the storage account.
The new version is in Preview and not GA currently. It might be not all functions available. you could also check the following characteristics.
No gateway is required to use the new VNet Integration feature。
You can access resources across ExpressRoute connections without any additional configuration beyond integrating with the ExpressRoute connected VNet.
The app and the VNet must be in the same region.
The new feature requires an unused subnet in your Resource Manager VNet.
Your app must be in an Azure App Service deployment that is capable of scaling up to Premium v2.
Your App Service plan must be a Standard, Premium, or PremiumV2 plan Production workloads are not supported on the new feature while
it is in Preview
The new VNet Integration feature doesn't work for apps in an App Service Environment.
You cannot delete a VNet with an integrated app.
Route tables and global peering are not yet available with the new VNet Integration.
One address is used for each App Service plan instance. Since subnet size cannot be changed after assignment, use a subnet that can
more than cover your maximum scale size. A /27 with 32 addresses is
the recommended size as that would accommodate an App Service plan
that is scaled to 20 instances.
You can consume Service Endpoint secured resources using the new VNet Integration capability. To do so, enable service endpoints on the
subnet used for VNet Integration.
I can't get vNet integration between an Azure App Service / WebJob and it's connected Storage Account to work correctly. I have added both the App Service and the storage account to the same vNet and enabled service endpoint binding for Microsoft.Storage. From what I can see in the docs, this is what is needed to get the communication to work between the services. Unfortunately, I get this error in the WebJob log when I try to run it:
"Unhandled Exception: Microsoft.WindowsAzure.Storage.StorageException:
The remote server returned an error: (403) Forbidden. --->
System.Net.WebException: The remote server returned an error: (403)
Forbidden."
If I disable the firewall on the storage account everything works just fine.
All the services are placed in the same resource group and region (West Europe).
I have tried both the "normal" (with gateway) and the new (Preview) vNet integration version on the App Service and both are failing the same way.
I am not using ASE (App Service Environment).
I have also added the following exceptions on the storage firewall:
Storage firewall exceptions
First, when you allow the set of trusted Microsoft services to bypass the network rules. These services will then use strong authentication to access the storage account.
In this case, you may think Microsoft.Networking service will be allowed in firewall rule. But basically, VNet Integration does not mean App Service is inside a VNet. VNet Integration gives your web app access to resources in your virtual network but doesn't grant private access to your web app from the virtual network. We usually used to securely access the resource in a VNet.
If you want to put your App Service in a VNet, you need to deploy it in App Service Environment, then it's already in a VNet.
Alternatively, you could whitelist the outbound web app service IP address in the firewall rule of the storage account.
Hope this helps, feel free to let me know if you have any concerns.
I've struggled myself on this topic.
First off, if you're restricting access to storage using the firewall you need to add your VNET to the storage firewall. Use your delegate subnet when adding your VNET.
When you add the private link between your storage and your VNET, Azure creates a private DNS zone but your app doesn't automatically use it, even when integrated to the VNET.
You can find more here https://learn.microsoft.com/en-us/azure/app-service/web-sites-integrate-with-vnet
But specifically this passage applies:
After your app integrates with your VNet, it uses the same DNS server that your VNet is configured with. By default, your app won't work with Azure DNS private zones. To work with Azure DNS private zones, you need to add the following app settings:
WEBSITE_DNS_SERVER with value 168.63.129.16
WEBSITE_VNET_ROUTE_ALL with value 1
These settings send all of your outbound calls from your app into your VNet and enable your app to access an Azure DNS private zone. With these settings, your app can use Azure DNS by querying the DNS private zone at the worker level.
You can test the DNS resolution your app is using by opening the debug console and using the NameResolver command
NameResolver mystorageaccount.blob.core.windows.net or
NameResolver mystorageaccount.queue.core.windows.net
should return your private address. If not you have a DNS issue.
I have an Azure Storage account and need to enable the storage firewall.
I have added the outbound IP addresses of my App Service, but the firewall still prevents access. (I know that these addresses can change, but they change predictably, so I can live with that.)
Is there a solution to grant an App Service access to the Storage account other than disabling the firewall (and other than using an ASE, which isn't an option)?
So it turns out that in a new Azure Storage account with a new App Service, setting the storage firewall to the outbound IPs of the App Service does work as expected. Unless the client browser is actually doing the download, adding the client's IP is not required.
Edit
This only works reliably when the storage account is in a different data centre to the App Service. When they are both in the same data centre, an internal outbound address (e.g. 10.x.x.x) is presented from the App Service to the Storage account. Internal addresses cannot be added to the Storage firewall.
If you access your web app service from on-premises networks, you need to grant access from your on-premise networks to your storage account with a public Internet-facing IP address used by your network. You can get more details from Grant access from an internet IP range
If you have VNet Integration with your apps. You should first enable service endpoints for storage in the VNet. You can refer to Grant access from a virtual network.