10 Questions to Ask When Choosing a DNS Security Product

The DNS security market spans everything from global cloud services to on-premise platforms, and on paper the products sound alike: they all "block malicious domains". The differences only become visible when the right questions are asked. The ten questions below collect what teams evaluating a DNS security investment should ask vendors — and themselves.

1. Where are our DNS logs processed and stored?

This is the most differentiating question. With cloud-based services, your queries are analyzed and stored on the vendor's infrastructure — usually abroad; with an on-premise model, the data never leaves your servers. The answer directly determines your data protection compliance, your audit posture and, for public institutions, your regulatory standing. If the answer is "a regional data center", pin down which country the logs live in and which law they are subject to.

2. Does protection continue if the internet connection drops?

With cloud services the resolution chain depends on the vendor; an outage on either side suspends protection and visibility. In the on-premise model, threat intelligence and policies are kept locally, so protection continues uninterrupted. If you operate an air-gapped network, this question becomes an eliminator: can the product be installed on a closed network and updated offline?

3. How do you detect unknown threats?

Every product has a blocklist; the difference shows with threats that are not on it. Ask for concrete answers: what method drives DGA detection? Which signals are monitored for DNS tunneling? Are NXDOMAIN and fast-flux anomalies evaluated? Probe the architecture behind the sentence "we use AI": where does the model run, and does the interface show the reasoning behind each verdict?

4. Can it catch country-specific threats?

Global intelligence feeds can lag on targeted and local campaigns. Ask whether intelligence from national sources is built into the product — for phishing infrastructure aimed at your country, lookalike domains impersonating public institutions, and regional attack waves.

5. Will we see the user behind each query?

An IP address alone is not enough for incident response; in a DHCP environment, yesterday's IP belongs to a different device today. Ask how Active Directory user mapping works: does it require an agent on every client, an extra appliance, or is it agentless? Deploying agents to every client is a serious operational burden on large networks.

6. What will we have to change in our existing infrastructure?

A well-designed DNS security layer sits in front of your existing DNS servers and does not touch them; the only client-side change is the DNS address in DHCP. Clarify whether the product requires a specific firewall brand, a specific DNS server, or extra hardware. Ask about the rollback plan too: how many steps does it take to take the product out of the path?

7. How does the branch and remote site architecture work?

Placing an appliance at every site multiplies cost; hauling all traffic to headquarters adds latency. An edge-central architecture — a lightweight component making local decisions at the branch while the center manages policy and visibility — strikes the balance. Give vendors your branch count and bandwidth constraints and have them walk you through the architecture.

8. How does it integrate with our SIEM and existing security stack?

If DNS-layer verdicts do not flow into your SIEM, the visibility gain is incomplete. Ask which formats (CEF, LEEF, Syslog) and transports (UDP, TCP, TLS) are supported, and whether integration requires an additional product or license.

9. How long can logs be retained?

With cloud services, retention is usually tied to the subscription plan, which limits your retrospective investigation window. Confirm whether the product can meet the retention period your regulations require, whether old logs remain searchable, and where the archive physically resides.

10. What is the total cost — and the support model?

Add to the license price: mandatory hardware or add-on products, cloud fees that scale per user or per query, integration effort and support. Make the support model concrete: when something breaks, do you reach the team that develops the product, or a distributor chain? For domestic products, price advantages for local software in public tenders also belong in the total assessment.

Finish the evaluation with a test

If the answers hold up, the final step is seeing it on your own network: request a proof-of-concept deployment and observe it with real traffic for a few weeks. You can also review how products compare against the same criteria on the Obsolix comparison page.