How to – Control Azure DDoS Plan Deployment using Azure Policy

Recently I saw that there was an update released for an Azure Network Security Demo. This is an excellent lab, with a well maintained repo and several services you can really make use of.

However, I noticed that it includes Azure DDoS Protecting on the Standard tier and does not carry a warning relative to the cost due to pricing model. This is the number one prohibitive factor I see with customers when discussing enabling DDoS Standard. While the resources provisioned as a whole are by no means “cheap” DDoS is the only one that carries a monthly as opposed to hourly rate.

Don’t get me wrong, this isn’t a negative post about DDoS Standard, I think it’s a good service. Take a look at the below benefits it offers over the Basic offer:

Azure DDoS Protection Service Comparison

Also a list of the features and functionality it can provide is here on Docs.

But as I said, the cost is prohibitive, but what does that mean? Well take a look at the breakout of how the service is charged, vs something like Azure Firewall (also included in the lab).

Notice the main difference? It’s how the run rate is calculated. Firewall is per hour and DDoS is per month. This is restrictive, especially on a platform advertised often as “per-minute billing”. However, if you need the services offered, at least at you have a set price. The main challenge is for companies willing to pilot this and being met with this cost. Similarly, labs that include it for a demo that you may only need for a day or even a couple of hours.

Hat tip to Peter De Tender who spotted a change on the FAQs that if only the service is only active for a portion of time, you will receive a pro-rated bill. I haven’t seen this yet in practice, but if it’s public information you should be able to count on it!

So, based on cost alone, perhaps it is justification to block DDoS Standard from being deployed in your subscription? If that is your requirement, it is easily met via Azure Policy. The built-in policy below is perfect for this job

You can then simply choose the DDoS options as your parameters and prevent the service from being activated and avoid a cost shock!

Conversely, regardless of cost, perhaps you need it as part of a compliance or regulatory requirement. If so, Azure Policy can help here too! There are two built-in policies relative to DDoS enablement, however, if you need it to remediate rather than just audit, choose the below policy, ensuring you have a DDoS Plan created in advance.

The final point to note here is that DDoS is recommended as part of the Azure Security Benchmark if you are using Azure Security Center on the Defender tier. It requires Standard to be enabled to meet the control requirement, so be cautious and aware of committing to adhering to this standard!

As always, if there are any questions or feedback please get in touch! And remember, keep using #AZNet for your Azure Networking content!

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