We have set up a VPN gateway and used it to connect an on-premise network with an Azure VNet. We have successfully tested a number of scenarios
communication from VMs to on-premise DBs
communication from on-premise computers (desktops and servers) to VMs (SSH etc.)
communication from on-premise computers (desktops and servers) to services with Private Link endpoints (App Serivces, DBs etc.).
The use-case we are now attempting is to access an on-premise DB from an app-service. I have integrated the app-service to the routed VNet and also added a service endpoint to this VNet. I have seen infos that this should work but it is not getting though.
A second question is what is the actual source ip of the app-service when it connects to the on-premise server. Surely not the outbound IPs? These are non-exclusive public IPs. Opening these on our VPN firewall would be a risk. In this case is the solution to also give the app service in question a private link endpoint. Will it's source IP then be the private IP of the PL?
Private Endpoint is only used for incoming flows to your Web App. Outgoing flows will not use this Private Endpoint, but you can inject outgoing flows to your network in a different subnet through the VNet integration feature. When you enable Private Endpoint to your Web App, the access restrictions configuration of the Web App is not evaluated. So in this case, I don't think you need to set the service endpoint Microsoft.Web for your web app if you have set it. Reference from using Azure private endpoint for Azure web app.
When regional VNet Integration is enabled, your app makes outbound calls to the internet through the outbound addresses that are listed in the app properties portal. Regional VNet Integration works by mounting virtual interfaces with addresses in the delegated subnet. If WEBSITE_VNET_ROUTE_ALL is set to 1, all outbound traffic can be sent into your VNet. So the source IP address will be from the integrated subnet when app service comes to the on-premise server as the #silent's comment. Reference from how regional VNet Integration works. Please note that the feature supports only one regional VNet Integration per App Service plan.
Related
I deploy my web application to an App Service instance on Premium tier. My web application makes outbound requests to external resources on the Internet.
In order to secure the connection with one of these external resources so I can reach it with a private IP address, my plan is to create a Site-to-Site VPN from Azure to Oracle Cloud Infrastructure (where the external resource resides). Then, I plan to use the VNET Integration for outbound traffic and connect my App Service to my VPN.
My question is - will the web application still be able to reach the other external resources on the Internet with their public IPs? I believe the answer is related to routing tables but I can't wrap my mind around it.
Just because you integrate a Regional VNet (I'm assuming) doesn't mean the app service won't be able to make outbound connections. Pretty much like
When you integrate your app service with your VNet that has the site-to-site VPN, traffic from your app service will traverse the Azure network rather than going out to internet, assuming your app service is using an RFC1918 address for your infrastructure. If you want to secure the traffic even further, then your app service would need to be hosted inside an App Service Environment
I have two NodeJS App Services.
They can connect to each other with no problem using the URL which is created for App Services by default. (That is through the public internet.)
Then I successfully enabled VNet Integration for both App Services, and assigned the same VNet and also subnet two both of them.
How should I modify the connection URL now to connect to appservice2 from appservice1 (without using the URLs which are publicly available on the internet)?
I could not find any host name or IP address information in Azure Portal using which I could have successfully established the connection.
Thanks for any suggestions!
When you want two app services to connect to each other over a private network, there are generally two steps you have to take to set this up correctly. Note that the app service URL will always stay the same, it is only the networking part that changes.
Both app services should have vnet integration enabled, which allows the app service to route its traffic through the vnet.
If you want others (e.g. another app service) to connect to an app service via a vnet you can choose between:
a) Service endpoints
b) Private endpoints
Reading your question, I assume you completed the first step correctly. But you have to complete either step 2a or 2b to get this to work properly. I would recommend you choose service endpoints because they are more straightforward than working with private endpoints. Below you'll find a detailed description and considerations for every step.
1. Vnet Integration
The subnet you use as an integration subnet has to be a dedicated subnet. This means it is only used for vnet integration.
Only one app service plan can be used with this dedicated subnet, this one app service plan may include multiple app services.
If there is a network security group attached to that subnet, it needs to allow outbound traffic.
If there is an azure firewall attached to your vnet and you want to make a call to a public endpoint, it should allow outbound traffic.
Vnet route all should be enabled if you want all the outbound traffic to travel over the vnet.
If you want to read more, I would recommend reading this documentation.
Here is a simple example of how you would create vnet integration by selecting the dedicated subnet:
Service Endpoints
Service endpoints allow you to lock down inbound access to your app so that the source address must come from a set of subnets that you select.
Service endpoints are automatically provisioned by azure when you enable access restrictions to the app service.
This is a much simpler alternative to private endpoints.
Does not work in large-scale networks where you want to connect from an on-prem network to an azure vnet.
You may turn to this documentation to read about all the features and limitations of service endpoints.
Here is an example of how you would enable services endpoints for your app service by creating an access restriction:
Private Endpoints
Private endpoints also need a subnet, but you can connect as many private endpoints to the subnet as there are IP addresses available.
When you use private endpoints, you also need to have a private DNS zone. Otherwise, the app service URL does not resolve correctly to an IP address.
Private endpoints are more complex than service endpoints because of the extra subnet and DNS requirements.
Here is a nice tutorial that let's you set up an app service with private endpoint.
The following example shows you how to create a private endpoint for your app service. You have the option to let azure create a private DNS zone automatically, or you can do this manually:
If you want to access app services without public internet, then enabling VNET integration in those services alone won't be enough. You need to create a private endpoint that provides the IP from the virtual network to access the app service internally within the VNET and it also disables public access to the app service over the internet. Also please be aware that the private endpoint implementation will have some cost implications as well.
If your requirement is just to establish a secure connection between your virtual network & app service and to avoid access over the public internet, a service endpoint is the simplest solution. If you also need to access the app service from on-premises through an express route or Azure Gateway, a regionally peered virtual network, or a globally peered virtual network, Private Endpoint is the solution.
Steps to set up a service endpoint are detailed in the provisioning service endpoint link
Steps to set up a private endpoint are detailed in the connect to the web app using private endpoint link
Also if you want to deep dive into private endpoint configuration for app service, I would recommend you to read through the following tutorial
We have three App Services in Azure (API1, API2, API3).
API2 is getting data from CosmosDB.
API3 is getting data from other CosmosDB.
Main API1 calls API2 to get some data. Then using this data calls API3.
We have poor performance of API1 and we are trying to figure out why. We noticed that there are too many connections in metrics. Also we have issue with SNAT ports.
We tried to setup these APIs to the same VNet but it doesn't help and we are not sure how to set up it correctly.
Do you have any idea what we should setup?
UPDATE:
Seems like VNet helped us with SNAT ports issue but performance of API was still very poor.
What really helped us was change from Windows to Linux. When all APIs runs on the Linux servers we don't see any connections anymore.
Not sure what's specific configurations about three APIs on your side. If you want to use IP from Vnet instead of an external one, you can use a separate environment ASE.
Alternatively, you can use a private link to the app service. By using Private Endpoint, you can connect privately to your web app. Read Connect privately to a web app by using Azure Private Endpoint (Preview).
Today, you can secure this connection using VNet service endpoints
which keep the traffic within the Microsoft backbone network and allow
the PaaS resource to be locked down to just your VNet. However, the
PaaS endpoint is still served over a public IP address and therefore
not reachable from on-premises through Azure ExpressRoute private
peering or VPN gateway. With today’s announcement of Azure Private
Link, you can simply create a private endpoint in your VNet and map it
to your PaaS resource (Your Azure Storage account blob or SQL Database
server). These resources are then accessible over a private IP address
in your VNet, enabling connectivity from on-premises through Azure
ExpressRoute private peering and/or VPN gateway and keep the network
configuration simple by not opening it up to public IP addresses.
For more information, you could read here.
I've got an Azure app service that I'd like to use to run some software that requires licensing. The license is provided via a server on our internal network. The issue being finding a way to connect to this server.
The first option is to provide a fixed license that ties to the MAC address. However I don't think this will be possible from an app service, as it does not really have a MAC address? Can I provide a VNI to it and obtain a fixed MAC address that way?
What other options are there? Can the app service be tied to a VNET that can tunnel to the on-premises resource? Should I use a VM with a VNI instead of an app service? Any resources on these kind of problems would be appreciated.
I have used Azure Relay to connect my on-prem service with my app service. Not sure if you have already considered this option.
If your requirement is to establish a connection between your on-prem service and you app service, check out this https://learn.microsoft.com/en-us/azure/service-bus-relay/relay-what-is-it
Hope this helps
You could use VNet Integration with Azure App service and Azure VPN gateway to connect to on-premise resources. VNet Integration is used only to make outbound calls from your app into your VNet. There are Regional VNet Integration and Gateway-required VNet Integration.
How regional VNet Integration works
Regional VNet Integration works by mounting virtual interfaces with
addresses in the delegated subnet. Because the from address is in your
VNet, it can access most things in or through your VNet like a VM in
your VNet would. The networking implementation is different than
running a VM in your VNet. That's why some networking features aren't
yet available for this feature.
How gateway-required VNet Integration works
Gateway-required VNet Integration is built on top of point-to-site VPN
technology. Point-to-site VPNs limit network access to the virtual
machine that hosts the app. Apps are restricted to send traffic out to
the internet only through Hybrid Connections or through VNet
Integration. When your app is configured with the portal to use
gateway-required VNet Integration, a complex negotiation is managed on
your behalf to create and assign certificates on the gateway and the
application side. The result is that the workers used to host your
apps are able to directly connect to the virtual network gateway in
the selected VNet.
For more information, you could read this blog---How to Connect Azure Web Apps To On-Premises
In addition, If you need more control of the application deployment and less scale out or in than the Azure app service. You could host your application on the Azure VM, then set up a VPN gateway in that VNet where Azure VM locate, it allows access to the on-premise resources from your Azure VM as usual in the internal network.
Trying to secure an API apps endpoint without Azure Active Directory. I have seen examples of NSG for securing SQL Server endpoints.
But with PaaS services (web apps / api apps/ logic apps) since they dont have VNETS I am bit confused as to how NSG will restrict traffic.
On Api app blade I see a "Networking" option and clicking that takes me into setting up VNET integration. When I click VNet setup starts gateway setup and configuration.
Has anyone done something similar where they secure backend api services using NSG and not API Gateway or AAD authentication.
Thanks !!
If you integrate the app service with a vnet, you can use NSGs to restrict the traffic, but only for the traffic connecting via the private network. vnet integration works with a vpn connection, hence the required deployment of a gateway on the vnet.
In this setup, the api app will still be accessible on the internet and that traffic will not be affected by the NSG, since it does not touch the vnet.
If you want to secure incoming traffic based on network origin you could implement that in application, but I would recommend against relying solely on that for security.