Documentation says "ILB only mode - This is currently not supported. Public and ILB mode together is supported". However, when I create a Standard_v2 AppGw I can't create a listener on both the public and private frontend-ip. It erros out with the message below.
Creating listeners on either the private or public frontend-IP works. Changing the frontend-IP of a listener also results in the error below.
Error: "Failed to save configuration changes to application gateway. Error: Two Http Listeners of Application Gateway are using the same Frontend Port."
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@geertn Even if you are doing both a public and private listener they cannot use the same port. You should be able to make a new Front End IP Configuration using a different port, and you can always direct the traffic to the same backend port or VMs if needed.
If you would like us to enable this feature in the future, please leave your feedback Here.
We will now proceed to close this thread. If there are further questions regarding this matter, please tag me in your reply. We will gladly continue the discussion and we will reopen the issue.
@geertn Is that feedback item still awaiting moderator approval after 18 months?
@SvenAelterman When I log into uservoice I see "Your idea is being processed and will appear shortly". However it seems that the idea has been online at a point since it received 111 votes and several comments.

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@SvenAelterman When I log into uservoice I see "Your idea is being processed and will appear shortly". However it seems that the idea has been online at a point since it received 111 votes and several comments.