Can you tell me whether the following scenario could be possible?
I want to access an Azure web app through a reverse proxy running on-premise.
The proxy will be responsible to authenticate the users, add a JWT (or SAML) to the request and forward it to my Azure Web App.
The Azure Web App will authorize (or not) the user to perform the request.
Potentially, there can be multiple reverse proxies on different sites.
Anybody has experience with such a setup?
Of course, this prevent the Web App to be globally available but that is not an issue.
Thanks,
An Azure Web App always has a public name and IP, therefor it is possible to bypass your reverse proxy and access directly the app using its public name, or IP.
However, if you need to make the traffic between your reverse proxy and the app private, you got a few options. You can either run your app in a VM or in an App Service Environment. Both offer private network access, i.e. can be added to a virtual network and a VPN tunnel be built to your on-premises network.
Difference between an ASE and a VM is that the VM you manage and maintain, while the ASE is a private PaaS service, i.e. private app service managed and maintained by Microsoft, thus more limited in capabilities than a VM.
Pricewise, a normal Azure Web App is the cheapest option. VM or an ASE are considerably more expensive.
Related
I have an Azure Web App and an Azure SQL Server, both in the same subscription. Both of them are connected to the same VNet Subnet as shown in the below snapshots. The SQL Server is configured not to Allow Azure Resources and Services to access the server, as it should only permit access from either the connected subnet or a set of IP rules.
Unfortunately, the SQL Server is actively refusing any connection from the web app stating that the web app IP is not allowed to access the server.
The interesting thing is that I have the exact same configuration working on another subscription.
What could I be missing?
Snapshots:
1- Here you can see the web application connected to the "webapps" subnet
2- And here you can see the SQL Server connected to the same subnet
3- And that's the error I get
TLDR
The configuration is correct, but an app service restart may be required.
VNET Integration
The configuration of using a virtual network to connect a web app to a SQL database is correct: if the web app is connected to the same subnet/vnet which is allowed in the database's ACLs, and the Microsoft.Sql service endpoint is enabled on the subnet, the web app is able to communicate to the database. This is the whole reason for service endpoints: you do not need to configure with IP allowances on the database.
As to why the configuration still resulted in an error, it could be the order in which the resources were configured. We were experiencing the exact same setup and issue (which is what let me to this question)!
We connected our web app to the subnet/vnet but had not enabled the service endpoint on the subnet. We then added/allowed the subnet/vnet as an ACL in the database, during which we were prompted to enable the Microsoft.Sql service endpoint (we did). However, even after waiting ~20 minutes, we were still seeing the same connection issue.
However, once we restarted the app service, the issue went away and the web app could connect to the SQL database.
I suspect the issue is due to enabling the subnet's service endpoint after the app service was connected to the subnet. The app service must need a restart to refresh the app service's vnet config/routing.
Configuration NOT needed
Contrary to other answers, you do not need to configure firewall IP allowances nor enable access to Azure services and resources. In fact, there are downsides to both approaches:
Enabling access to Azure services and resources allows any Azure-based resource to connect to your database, which includes resources not owned by you. From doc:
This option configures the firewall to allow all connections from Azure, including connections from the subscriptions of other customers.
Unless you're using an App Service Environment (which is significantly more expensive than normal App Service plans), your web app's outbound IP addresses are neither static nor specific to your application. From doc:
Azure App Service is a multi-tenant service, except for App Service Environments. Apps that are not in an App Service environment (not in the Isolated tier) share network infrastructure with other apps. As a result, the inbound and outbound IP addresses of an app can be different, and can even change in certain situations.
The second point is further elaborated upon in this Github issue:
IPs are indeed shared with other App Service plans (including other customer's plans) that are deployed into the same shared webspace. The network resources are shared among the plans in a workspace even if the computing instances are dedicated (e.g. in Standard tier). This is inherent to the App Service multi-tenant model. The only way to have a dedicated webspace (i.e. outbound IPs) is to deploy an App Service plan into an App Service Environment (ASE) (i.e. Isolated tier). ASE is the only thing that offers true single-tenency in App Service.
So neither of the above options will truly harden your SQL database if you want to isolate communication from only your web app. If you have resources in the same subnet, using vnet integration is the correct way to solve the problem.
If resources cannot be in the same subnet, the solution is to use Private Endpoints.
Virtual networking in Azure is quite different from how it would work on premises.
I had similar problems in production environment and digging deep, the working solution (meeting security standards and create a secure connection to the database) was to create a private endpoint for SQL access in the virtual network. Then all the calls to the SQL were performed internally (it did not go on the internet), and the databases were denying all public calls.
In your case now, you deactivated the Allow Azure apps to access so when your app is trying to access the SQL the server checks the ip to find out if it is white listed or not. So fast solutions would be one of the following:
Enable Azure Web apps to access SQL
Find all outbound IPs of your web app and register them in you SQL firewall/ security settings.
If you talk about a proper production environment with security regulations I would suggest you go down the more tedious path of private endpoints.
You have to configure the outbound IPs from the app service in the sql fw.
You can find them under properties of your app service. Documentation.
The reason why is that the VNET integration doesn't give your app service an outbound IP in the VNET you configured it in, so the FW you configured doesn't work.
I have working web apps which access storage accounts and KVs. These storage accounts and KVs accept traffic from a particular subnet and the web apps have been configured to integrate with those subnets. I did face an issue where even after integration apps were not able to access these resources. What worked for me was, I changed the App service SKU from Standard to Premium and restarted the app. As you can see, it warns that "Outgoing IPs of your app might change". This is not guaranteed solution but it worked for me.. several times! Not sure about SQL server though. Private endpoint does seem like the way to go but you can give this a try.
Right now we have AD set up so access to our App Service is authenticated. But we need the website to have local access to some special applications. Since we can't install applications on an App Services, I THINK that means we need to run the website on a VM.
If that's the case, I'd like to not lose the ability for Azure AD to authenticate access to our VM. I'm sure we can use Azure AD to authenticate us while we RDP to the server, but can it also be used for when we expose our Web Application over HTTPS from the server?
Since we can't install applications on an App Services, I THINK that
means we need to run the website on a VM
Even though a VM is the simplest one, you do have other options to at least consider. Here is Microsoft's documentation comparing the various options along with scenario based recommendations.
Azure App Service, Virtual Machines, Service Fabric, and Cloud Services comparison
Quick Note:
Amongst the options discussed, avoid Cloud Services (classic) as far as possible, as they are legacy and on their way out. Also, if you still choose Virtual machine, do consider Virtual Machine Scale Sets for better scale and management options.
I'm sure we can use Azure AD to authenticate us while we RDP to the
server, but can it also be used for when we expose our Web Application
over HTTPS from the server?
Yes, it can be used even when you expose your web application over HTTPS from the server. Exposing over HTTPS would only involve opening up the port through NSG rules and SSL settings for your application in IIS. This will not impact you ability to RDP into the VM.
I am planning on using an outsourcing team for data processing and want to avoid them downloading or storing client data on their local machines. To facilitate this, I want to create an Azure VM in which they can do all their work (msoft office, etc.) and access an ASP MVC app hosted as an app service in Azure. The MVC app is integrated with the corporate AD and for the outsourcing logins I want to see if the request is coming from my VM or the internet (the latter gets denied). So far I have:
Created a ASP MVC5 app and an Azure VM
Connected the two via VPN (point to site)
When I attempt to go to the public URL for the website on the VM, I get the "this page can't be displayed" thing, which leads me to believe I'm on the right track (now I have to update the hostfile of the machine to the private IP of the mvc app service app?). How do I do the following:
Connect to the app service via web browser (this needs to be over the vnet so that I can pick and choose in the app code who can login outside the network)
Get the network ip of the app service so I can update the VM hostfile
Am I on the right track here? Thanks in advance!
Your understanding of Azure App service is not accurate. Azure App service cannot be accessed via a private IP. They already sit inside a private vnet. They can be only accessed via public hostname with a common DNS name (azurewebsites.net)
Your scenario requires the Azure Web app and the VM to reside in the same VNET, which is not possible. There is another offering called ILB ASE, which allows you to do this. But it's a more elaborate setup. See this for more information: Using ILB with AN ASE
In your scenario you can restrict access to the web app via IP Restrictions module. See this article: IP & Domain Restrictions in Azure App Service
I understand this not the solution u wanted. What you want can be achieved via ILB ASE, but that is an expensive and elaborate set-up.
HTH
you may want to try using cloud service, though MS recommends App Service, you requirement doesn't fit into App service..
Official documentation from MS: https://learn.microsoft.com/en-us/azure/cloud-services/cloud-services-startup-tasks-common
Block a specific IP address
You can restrict an Azure web role access to a set of specified IP addresses by modifying your IIS web.config file. You also need to use a command file which unlocks the ipSecurity section of the ApplicationHost.config file.
In a typical 3-Tier web app, you run web servers in public subnet, while app tier lives in private subnet. Is it possible to run similar architecture with Azure Web apps and Api apps?
I guess you can run Asp.NET Core Web App in Azure Web App and Deploy AspNet Core Web Api to Azure Api App, then make Api end point private so only Web app can talk to it? I see options like Google, Facebook et. as auth providers. Is that what you have to do to make API private?
D.
If you want that level of isolation, one (although expensive) option is an App Service Environment (ASE). Link to docs: https://learn.microsoft.com/en-us/azure/app-service-web/app-service-app-service-environment-intro
App Service Environments are ideal for application workloads requiring:
Very high scale
Isolation and secure network access
The public environment where you deploy by default is public. Your endpoints will be accessible to anyone anywhere, and it is up to your app to do the filtering. This can be done, e.g. through static IP address security settings in Web.config. The problem with that is that even then you can't know for sure what IP address your front-end will use for communication. There are multiple possible addresses it may use for outbound traffic, and those are subject to possible change.
You can see an example of IP restrictions here: restricting IP security
Of course you should also have authentication set up on your API. Documentation links:
https://learn.microsoft.com/en-us/azure/app-service/app-service-authentication-overview
https://learn.microsoft.com/en-us/azure/app-service-api/app-service-api-authentication
In line with what #juunas said above and a slight variant is to introduce Azure API Management Gateway in between Azure web app and Azure Api app. In standard tier API Gateway the IP address is fixed and doesn't change and you can use the API Gateway address in Azure API App web.config to whitelist.
I have a .NET Web Api project with several REST endpoints that I only want accessed by resources from within an Azure virtual network I have created. Resources such as Azure Functions and Azure Web Roles will access these endpoints only. In other words, I do not want the endpoints publicly available.
So, I configured the Web Api application with my virtual network but apparently I also need to add the Web Api application to an Application Service Environment (which are quite costly from what I have read). To quote the Azure documentation:
VNET Integration gives your web app access to resources in your virtual network but does not grant private access to your web app from the virtual network.
Do I indeed need to use an Application Service Environment and just deal with the costs or is there another way I can achieve what I want?
I do not want the endpoints publicly available.
Until now, Azure web app only supports for using an internal load balancer with the app service environment feature. If you want to make your Web API can only be accessed internally. An app service environment is required.
If you don't want to move your Web API to app service environment and your Azure function and web role have fixed ip addresses, you could configure the IP whitelist using ipSecurity configuration in your web API. For more information of ipSecurity, link below is for your reference.
IP and Domain Restrictions for Windows Azure Web Sites