DNS TCO: Software, appliance or cloud?

To maintain an Internet presence with DNS services, organisations have a number of options, including on-premise open source software, on-premise commercial software, a network appliance or a cloud-based cloud DNS server.

At Linuxpeak we often get asked: What’s the best option for DNS? There is no one definitive answer to that question as every organisation’s requirements are different, but in most cases a cloud-based DNS service is the best option in terms of cost and complexity. To calculate the “hidden” cost of DNS consider the following scenarios.

On-premise open source

Many organisations successfully provide DNS services by using open source software provided by the community. However, even if the software is free time must be spent configuring, managing and securing the software in addition to the cost of hosting a virtual or physical server. On-premise DNS services built with open source software involves:

  • Physical or virtual server costs
  • Platform hosting (power, bandwidth, etc)
  • Staff to configure and manage it (in-house or contractors)
  • Security auditing costs
  • Reliability and risk management (what if the server goes down?)
  • Contingency plan (if staff leave, etc)

On-premise commercial software

Running DNS services with a commercial product inside the organisation’s network shares many of the same aspects of servers built with open source components. The main differences being:

  • Less integration work (assuming the software runs okay out of the box)
  • Paid vendor support
  • More upfront software costs in the form of licence and/or maintenance fees
  • Even with a commercial software product, you still need to manage the platform and network reliability to ensure the maximum possible uptime.

A network appliance

Yet another method of providing DNS services is with an appliance on the corporate network. This involves installing a hardware appliance with the software pre-installed. Key factors about using a hardware appliance for DNS are:

  • Low integration work (the system should “just work”)
  • Needs to be physically installed in an office or data centre
  • Requires additional power and network capacity
  • Higher upfront costs in the form of device procurement and installation services
  • Still requires ongoing software updates

Adding all of these factors together results in a total cost of ownership (TCO) for DNS that is comparable with other enterprise software. Since DNS is a necessity for all organisations, it tends to be just hidden away in the background and only noticed when something goes wrong. Hence, many organisations do not audit DNS the way other software or IT services are audited.

At Linuxpeak whenever we ask people to take a look at how much DNS is costing them they reply to us by saying something “I never knew it was this involved”. The conversation then usually turns to “how can I reduce my cost and complexity?”

For example, if an organisation is spending $5000 per year (a very conservative estimate) on in-house DNS services – using any of the methods described here – then moving to a cloud DNS service can result in at least a 40 per cent saving.

Although there are various pros and cons between the different types of on-premise DNS services they all have one thing in common – they are dependent on the reliability of the corporate network. If the organisation’s network is offline then DNS is offline. While this is also true of cloud DNS services, multiple, geo-redundant name servers generally provide a greater level of redundancy than in-house DNS servers.

Then there is the scalability question: Will an on-premise DNS service scale to meet company demands during periods of high growth or business activity? Cloud-based DNS services tend to be engineered with scalability in mind.

While there is no one answer for the best approach to DNS hosting as every organisation is different, Linuxpeak recommends IT leaders consider the total value of DNS services to their business, including the cost of any downtime. Only after a thorough TCO assessment is performed will organisationed be better informed on which path to take for DNS services.

– The Linuxpeak DNS team