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Hardware Requirement

Recursive Server Hardware

Enabling DNSSEC validation on a recursive server makes it a validating resolver. The job of a validating resolver is to fetch additional information that can be used to computationally verify the answer set. Below are the areas that should be considered for possible hardware enhancement for a validating resolver:

  1. CPU: a validating resolver executes cryptographic functions on many of the answers returned, this usually leads to increased CPU usage, unless your recursive server has built-in hardware to perform cryptographic computations.
  2. System memory: DNSSEC leads to larger answer sets, and will occupy more memory space.
  3. Network interfaces: although DNSSEC does increase the amount of DNS traffic overall, it is unlikely that you need to upgrade your network interface card (NIC) on the name server, unless you have some truly out-dated hardware.

One of the factors to consider is the destinations of your current DNS traffic. If your current users spend a lot of time visiting .gov web sites, then you should expect a bigger jump in all of the above categories when validation is enabled, because .gov is more than 80% signed. This means, more than 80% of the time, your validating resolver will be doing what is described in the section called “How Does DNSSEC Change DNS Lookup?”. However, if your users only care about resources in the .com domain, which as of this writing, is 0.5% signed, then your recursive name server is unlikely to experience significant load increase after enabling DNSSEC validation.

Authoritative Server Hardware

On the authoritative server side, DNSSEC is enabled on a zone-by-zone basis. When a zone is DNSSEC-enabled, it is also known as "signed". Below are the areas that you should consider for possible hardware enhancements for an authoritative server with signed zones:

  1. CPU: DNSSEC signed zone requires periodic re-signing, which is a cryptographic function that is CPU intensive. If your DNS zone is dynamic or changes frequently, it also adds to higher CPU loads.
  2. System storage: A signed zone is definitely larger than an unsigned zone. How much larger? See the section called “Your Zone, Before and After DNSSEC” for a comparison example. Roughly speaking, you could expect your zone file to grow at least three times as large, usually more.
  3. System memory: Larger DNS zone files take up not only more storage space on the file system, but also more space when they are loaded into system memory.
  4. Network interfaces: While your authoritative name servers will begin sending back larger responses, it is unlikely that you need to upgrade your network interface card (NIC) on the name server, unless you have some truly out-dated hardware.

One of the factors to consider, but you really have no control over, is how many users who query your domain name have DNSSEC enabled. It was estimated in late 2014, that roughly 10% to 15% of the Internet DNS queries were DNSSEC aware, and since then Google DNS has become DNSSEC enabled and is used by a further 15% of global DNS users. This translates to roughly 25% to 30% of the DNS queries for your domain will take advantage the additional security features, which result in the increased system load and possibly network traffic.

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