IPv4 and IPv6 on External LoadBalancer

Question

I have an Azure Load Balancer, configured with:

• a public IPv4 address (static)
• a public IPv6 address (dynamic)

In DNS, I have:

• an A record for the website pointing to the IPv4 address
• an AAAA record for the website pointing to the IPv6 address

This results in my websites being available both on IPv4 and IPv6.

Recently, Azure changed the IPv6 address. The server wasn't rebooted, there was no problem with the subscription, there was no service disruption, it was just changed all of a sudden... no notification either. It was the first time in six months.

Now, I'm wondering how to cope with this situation more efficiently.

I have been thinking, but technically the following avenues are not valid solutions:

• Assign a *.cloudapp.azure.com DNS name label and pointing to it through a CNAME record, as DNS can only distinguish between IPv4 and IPv6 through A and AAAA records, not based on CNAME records. A public IP address and DNS label in Azure is always IPv4 or IPv6 and would thus result in different CNAME records.
• Configure the public IPv6 with a static address instead of a public address. When I try to change it, the error is that that option is not available for IPv6 addresses...
• Configure the idle time-out for the public IPv6 address to something else than 4 minutes. When I try to change it, the error is that that option is not available for IPv6 addresses...

Is my only option to create an Azure function and Logic App to monitor changes to the IPv6 address assigned to the External Load Balancer's DNS name and send a notification/change it in DNS when the address changes?

Answer 1

It is absolutely possible to have a static IPv6 with an Azure Load Balancer. Here is a doc outlining the process for creating a static IPv6 Public IP and associating it to a new Load Balancer.