Configure and verify Vnet in Azure - azure

I have created a Virtual Network next to its subnet and integrated it into three service applications and created the rule on the firewall of my SQL Azure server.
Everything is in the same Azure subscription and region
I need to know if it is enough to direct all the traffic between these instances through the virtual network or do I need to configure some other aspect.
And how can I query the data traffic to verify that the virtual network is being used?

Azure Virtual Network (VNets) allows to place Azure resources in a non-internet-routable network.
https://learn.microsoft.com/en-us/azure/architecture/example-scenario/private-web-app/private-web-app#architecture
Using Azure App Service regional VNet Integration, the web app connects to Azure through an AppSvcSubnet delegated subnet in an Azure Virtual Network.
Virtual Network only routes traffic and is otherwise empty, but other subnets and workloads could also run in the Virtual Network.
The App Service and Private Link subnets could be in separate peered Virtual Networks, for example as part of a hub-and-spoke network configuration. For regional VNet Integration, the peered Virtual Networks must be located in the same Azure region.
Azure Private Link sets up a private endpoint for the Azure SQL database in the PrivateLinkSubnet of the Virtual Network.
The web app connects to the SQL Database private endpoint through the PrivateLinkSubnet of the Virtual Network.
The database firewall allows only traffic coming from the PrivateLinkSubnet to connect, making the database inaccessible from the public internet.

Related

Azure virtual network not routing traffic between subnets for app services

We deploy to Azure app services and to ensure secure traffic between each service they are configured with out bound traffic on a virtual network subnet. Each app service must have it's own subnet, which is understandable, but to allow the app services to communicate we are having to add inbound ip restrictions for each subnet, on each app service.
As all the subnets for all the app services within an environment are on the same virtual network we were expecting the traffic to route between the subnets. In that way by connecting each app service to an out bound subnet and allowing traffic back in on that subnet it would also allow traffic from the other subnets of the virtual network.
I've read here Azure: Routing between subnets a response that state "Azure routes traffic between all subnets within a virtual network, by default. You can create your own routes to override Azure's default routing." but that does not appear to be happening for us.
Is there a setting we need to change or a route that must be added to allow us to have a single inbound rule from the virtual network that allows all traffic from all subnets of the virtual network.
We are splitting our process into micro app services but this is making security of inter-app traffic complex as each time we add an app service we must update all others with an additional inbound rule before it can communicate.
We also have a similar issue with managing access to the azure sql database where we have connected the sql to a subnet in the virtual network but traffic from the app services cannot access over that subnet.
Any advice please?

Create external network between Azure API Manager and a virtual machine

I have created an API Manager Service (AMS) in Azure with its subnet.
I have created a Virtual Machine with Ubuntu that exposes some APIs on the port 8000. It has a public IP and an internal IP (10.0.1.5). This is the network configuration.
I don't want a public IP on this machine. What I want is that only the AMS speaks with the Virtual Machine to expose the API.
I can't find a way to create a private network (or external network in the AMS point of view) between the AMS and the virtual machine. In the network configuration of the virtual machine, the AMS subnet is not available.
In a normal network I would create a NAT between the 2 subnets but in Azure I don't know how to do it.
Do you have any advice?
Create a Virtual network first in some region . Then , while creating APIM services go to the Virtual network tab and select type as external instead of none and select the same Virtual network that you have created earlier.
Once the APIM service is deployed then create a VM and while creating the VM go to the networking tab and select the same virtual network that you have used in APIM but different subnet for the VM (as APIM and VM cannot use same subnet , it is not supported in azure) . You can add a new subnet in the same Vnet for using it in the VM by going to the VNet resource you have created and in Subnets page clicking on add subnet.
(Note : All the resources must be in same region)
After this configuration is done the resources can communicate which are present inside the VNet even if they have different subnets. As by default resources under the same vnet can communicate in azure.

why Extra subnet for VNET integration for app services

Why do we have to create a new subnet or add the app service to an empty subnet in our vnet?
I don't understand the reasoning since I'm trying to use my app service (function app) as a reverse proxy to access the resources in the vnet.
By default, the Azure function is a PaaS as the other Azure Platform-as-a-Services that have inbound and outbound traffic over the Internet. We can host our applications without the need to worry about the maintenance of the servers and their operating systems.
To use Azure Functions to connect to resources in an Azure virtual network, we can use the VNet integration feature. To use this feature, we need to create a subnet in the virtual network for your function app to use. VNet Integration must be configured to use an empty subnet. It doesn't matter that your functions use a different subnet than your VM. The virtual network automatically routes traffic between the two subnets. Read Connect your function app to the virtual network
The extra empty subnet is used to hosting your app instance. To let the app instance outbound traffic work like from a VNet, Azure mounts NICs with assigned private IP addresses in that subnet. With VNet integration, your function app is connected to both the internet and your virtual network.
For more information, you may read How regional VNet Integration works and How gateway-required VNet Integration works
For an app to access resources in a Virtual Network, it needs to be either part of that network, or use a VPN gateway, which in turn can be used access resources inside the Virtual Network.
App Services provides 2 methods to communicate with resources in the Virtual Network:
Regional VNet Integration
Gateway-Required VNet Integration
With Regional VNet Integration, the infrastructure allocates a private IP interface on the VM that is hosting your Web App. This interface is allocated an IP address from the integrated subnets address prefix. This interface is later used to communicate with the VNet hosted resources. This is in a way similar to how IaaS VM work, however the limitation of this interface is that it can be only used for making outbound connections.
This way, if the ASP is configured to scale out to multiple VM's then each VM is allocated a corresponding private IP interface. However, the allocation of these IP address is limited to the subnets Address prefix. Nancy has already included this in her post. App Services have overlapped recycling so during scale up/maintenance, the App Service Plan may run on twice the number of VM's to ensure minimal downtime. However this also means, that the Integrated Subnet should have sufficient addresses available, so that these allocations can happen.
The IP Address of this interface is exposed via the environment variable WEBSITE_PRIVATE_IP. Here is a screenshot of my Kudu Console
If your site is running on multiple instances, then you can use the Instance menu to toggle through the instances.
With Gateway-required VNet Integration, there is a pre-requisite of provisioning a Virtual Network route-based gateway configured with an SSTP point-to-site VPN. In this case, the VM's hosting the Web App download the VPN package on the respective VM's to setup a VPN, and this is used to connect to the resources in the Virtual Network.
Even here, you can use the WEBSITE_PRIVATE_IP environment variable to see the IP Address used by the VPN client on the App Service VM.
HTH,
Kaushal

Azure Application Gateway not showing VM from other VNet in backend pool

When setting up the Backend pools of an Azure Application Gateway, I want to set a specific VM in the pool.
This VM is in another VNet, and I've set up peering between the App Gateway's VNet and the VM's VNet.
Still, when I choose Virtual Machine as the target type of the Backend pool, the list is empty and I don't see any VM.
What's the problem? Am I missing something?
It seems that you only could see VMs in the same VNet as the application gateway located when you select the virtual machine as the target type of the backend pool.
If you have VNet peering, you can just add the internal IP of the VM to target the backend pool.
A backend pool routes request to backend servers, which serve the request. Backend pools can contain:
NICs
Virtual machine scale sets
Public IP addresses
Internal IP addresses
FQDN
Multitenant backends (such as App Service)
If you use internal IPs as backend pool members, you must use virtual
network peering or a VPN gateway. Virtual network peering is supported
and beneficial for load-balancing traffic in other virtual networks.
Reference: https://learn.microsoft.com/en-us/azure/application-gateway/application-gateway-components#backend-pools

Azure web app accessing service fabric's virtual network

I have a Service Fabric cluster hosting many legacy WCF services and I would like to connect an Azure App Service (running a website) to the fabric cluster's VNET, such that it can communicate with the WCF services in the cluster.
I connected my fabric cluster's VNET to an existing virtual network of our organization using VNET peering and I can connect to the WCF services from VMs within the existing virtual network.
However, when connecting from the app service, I got the following error:
Could not connect to net.tcp://10.0.0.250:8020/. The connection attempt
lasted for a time span of 00:00:00. TCP error code 10013: An attempt was made to access a socket in a way forbidden by its access permissions 10.0.0.250:8020.
I have configured an internal load balancer and its working ok if I connect from within the virtual network. Does anyone know why it doesn't work for the web app?
If you want to access the resources in a VNet from Azure App Service, you could enable networking for app service. Note that
VNet Integration gives your web app access to resources in your
virtual network but doesn't grant inbound private access to your web
app from the virtual network. Private site access refers to making
your app only accessible from a private network such as from within an
Azure virtual network. VNet Integration is only for making outbound
calls from your app into your VNet.
There are two versions of VNet integration, you could use Regional VNet Integration if service fabric's virtual network in the same region as your web app.

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