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Security & Compliance · Engineering, IT & AI
Should you build or buy Protective DNS / DNS Filtering?
Protective DNS and DNS filtering software intercepts DNS queries to block resolution of domains associated with malware, phishing, command-and-control infrastructure, and unwanted content categories before a connection is established. It operates as a security control that doesn't require agents on endpoints, making it one of the broadest-coverage, lowest-friction security controls an organization can deploy.
The build-vs-buy decision for Protective DNS / DNS Filtering turns on whether your threat model requires the continuously-updated threat feed quality and global anycast infrastructure that vendors aggregate from billions of queries, or whether the policy routing logic your team could build provides adequate coverage; the feed is the product, not the resolver.
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Last assessed June 2026 · re-scored quarterly via The Continuum.
Build it, buy it, or bridge?
| Build it | Buy it | Bridge (buy, then extend) | |
|---|---|---|---|
| Cost shape | Unbound and CoreDNS are free resolvers; threat feeds are the insurmountable cost | NextDNS at $1.99/mo, Cloudflare Gateway free tier; already priced at commodity | Buy the threat feed service; extend with custom allow/block lists for org-specific domains |
| Time to value | Resolver deploys in hours; threat feed quality gap exists from day one | Minutes to activate Cloudflare Gateway or NextDNS; instant threat coverage | Buy for immediate threat blocking; extend with org-specific domain policies |
| Differentiation captured | Custom DNS policy for specific internal naming and application needs | Vendor threat feed updated continuously from billions of queries across all customers | Vendor's global threat intelligence; org-specific allow/block list overlaid on top |
| AI feasibility today | DNS routing logic is trivially buildable; the threat classification model is not | Vendors apply ML to billions of queries to identify new C2 and phishing domains | Buy global threat intelligence; build domain policy management tools on top |
| Who it fits | Only orgs requiring complete DNS data sovereignty and willing to operate their own threat feed | Any organization; entry point is free to $1.99/mo for most use cases | Enterprises layering org-specific DNS policy on top of a vendor's threat blocking baseline |
When building Protective DNS / DNS Filtering makes sense
Building a DNS resolver with Unbound or CoreDNS is technically straightforward and takes hours. The challenge is the threat feed. DNS filtering security value comes from continuously classifying which domains resolve to malware, C2 infrastructure, and phishing, using signals aggregated from billions of queries across a global customer base. That classification model isn't replicable from a single organization's DNS traffic. A self-hosted resolver with manually maintained blocklists provides a fraction of that coverage and requires ongoing threat intelligence operations to stay current. The build case exists only for organizations that need complete DNS data sovereignty, where sending all DNS queries to a cloud provider is a regulatory or confidentiality concern, and who are willing to operate their own threat intelligence capability as a separate investment.
When buying Protective DNS / DNS Filtering makes sense
Buying earns its keep almost unconditionally, and the pricing makes it an easy decision. NextDNS costs $1.99 per month for personal use, and Cloudflare Gateway has a free tier. Cisco Umbrella and DNSFilter add enterprise features like reporting, per-policy user group controls, and compliance documentation at higher price points, but the threat blocking is available at near-zero cost for most organizations. The security value, blocking C2 and phishing domains before any connection is made, is immediate and broad-coverage. Running a custom DNS resolver without a continuously-updated threat feed provides the infrastructure without the security function. The build case really only applies when DNS data sovereignty is the driving requirement.
Protective DNS filtering is a global infrastructure play. The threat detection quality from platforms like Cloudflare Gateway and DNSFilter comes from aggregating query patterns across billions of DNS lookups, not from clever routing logic that any team could replicate. Cisco Umbrella and similar platforms maintain threat feeds updated by dedicated intelligence teams. The filtering logic itself is trivial. The feed is the product.
Buying earns its keep almost unconditionally here. NextDNS is $1.99 per month for personal use, and Cloudflare Gateway has a free tier. The category has already priced itself toward commodity for most use cases. Open-source recursive resolvers like Unbound and CoreDNS handle the protocol, but without a continuously-updated threat feed, they provide no security value. The build case gets interesting only for organizations that want complete control over DNS data and are willing to operate their own threat feed, which is a different and substantially larger project than replacing the resolver.
Representative vendors
DNSFilterCloudflare Gateway (Zero Trust)
and 3 more, scored in B4 Pro
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Frequently asked
- What is Protective DNS / DNS Filtering?
- Protective DNS and DNS filtering software intercepts DNS queries to block resolution of domains associated with malware, phishing, command-and-control infrastructure, and unwanted content categories before a connection is established. It operates without agents on endpoints, making it one of the broadest-coverage, lowest-friction security controls an organization can deploy.
- When does building Protective DNS / DNS Filtering make sense?
- Building a DNS resolver is technically trivial but the threat feed is not replicable. The build case exists only for organizations requiring complete DNS data sovereignty and willing to operate their own threat intelligence capability, which is a substantially larger project than replacing the resolver.
- When does buying Protective DNS / DNS Filtering make sense?
- Buying earns its keep for almost any organization. The category is already priced at commodity: Cloudflare Gateway has a free tier, NextDNS is $1.99/mo. The threat feed quality from vendor platforms aggregating billions of queries is not replicable from a self-hosted resolver.
- What are the main Protective DNS / DNS Filtering vendors?
- Representative vendors include DNSFilter, Cisco Umbrella, Control D, Cloudflare Gateway (Zero Trust). B4 Pro scores the full set.
The B4 Index scores every software category on two axes, strategic differentiation and AI feasibility, to
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