Azure web app request is not going through VNET after inegration

0
votes

I have created one Web app on Azure portal and its integrated with subnet under specific VNET. Now, when I am trying to do telnet to one of my organisation's internal relay server IP from my web app its not getting connected. The request is going from web app's APIPA address range not from subnet's address range. I checked the IP as well of the web app using ifconfig and I found out that its taking from APIPA address range not from subnet one.

Any idea what steps do I need to take so that web app will take IP from subnet address range of the VNET not from APIPA address range.

Thanks in advance.

1
azureazure-web-app-serviceazure-virtual-network

1 Answers

1
votes

After my validation, when the app service on Linux is integrated with a virtual network. There is an extra NIC binding to the app service. It's IP address from APIPA address range. It looks like a design behavior as the app service on Linux is running in a standard Docker Container, read here. Also, for a normal app service is a multi-tenant environment, you can not get a dedicated IP address unless you are using a dedicated environment---ASE, read here.

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Furthermore, from how regional VNet Integration works, you will see the app service integrated with a vNet is not the same as a VM from a VNet.

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.

In this case, if you wan assign a private IP address for app service, you can use Azure Private Endpoint with web apps(Preview). Read this blog for more details.

Azure Private Endpoint provides private IP address access by using a network interface controller (NIC) attached to a virtual network subnet for an Azure web app, allowing access from an on-premise VPN or ExpressRoute. Implementing an endpoint effectively blocks the public inbound access. This technology is very similar to an internal App Service Environment (ASE) but much cheaper.