Azure web app is using an outbound IP that is not listed.

Question

Hi,

Our Azure Web App has changed outgoing IP to one that is not listed in either Outbound IP addresses or Additional Outbound IP addresses.

We have checked both the portal and using the command;

az webapp show --resource-group <group_name> --name <app_name> --query outboundIpAddresses --output tsv

All of the usual outbound addresses are in the range of 20.xx.xx.xx

In Kudu we used curl -s https://api.ipify.org

and the outbound IP it is using is 104.209.xx.xx

We have not made any changes that would trigger an outbound IP change, but even if we did, it should be in the Additional Outbound IP addresses list.

We can work with this new IP. This does present a problem for us if the azure app is going to randomly change outgoing IPs to one that is not listed anywhere.