DNS Probe monitoring with Topologix

Infrastructure & Networking

Synthetic DNS monitoring with zero backend — every configured resolver is queried independently each poll, measuring resolution success and latency, validating expected answers, comparing SOA serials across the pool for zone convergence, and probing the TCP/53 listener.

Requirements

  • UDP and TCP reach on port 53 from the Topologix server — or a proxy agent for LAN-only resolvers and internal zones.
  • No credentials and nothing to install — it speaks the plain DNS wire protocol.

1 · Set up the integration

  1. Open the Integrations pageClick Integrations in the toolbar and pick DNS Probe from the catalogue.
  2. List the resolversOne DNS server per line (IP or host) under Resolvers / name servers — this is the default pool every source probes. Optional Query timeout (ms) (default 3000) and Connect via proxy for LAN-only zones.
  3. Create, then verifyClick Create, then reopen the integration and click Test — it sends a root-SOA query to each resolver and reports how many answered. A resolver that refuses the root query still passes if its TCP/53 listener is up.
The integration catalogue — DNS Probe found via search.
The integration catalogue — DNS Probe found via search.
The DNS Probe configuration drawer with example values. Every screen in this guide is the real product.
The DNS Probe configuration drawer with example values. Every screen in this guide is the real product.
Target on a private network? Route it through a proxy agent. Proxy agents run inside your network — behind NAT, on a management VLAN, in an air-gapped segment — and reach targets the Topologix server can't. The agent polls the server every 15 seconds for its assignments, runs the checks locally, and pushes results back every 5 seconds, so no inbound firewall rules are ever needed. Set a default proxy on the integration; every metric source can override it. If a proxy goes offline, its sources are marked stale within ~90 seconds and the last known values stay visible.

2 · Add it to a flow

  1. Select the DNS nodeClick the node, open Metrics, then + Add and choose the DNS Probe integration.
  2. Define the probeEnter the Record to resolve (FQDN) and a Query type (A, AAAA, CNAME, MX, TXT, NS, SOA, PTR, SRV). Optionally set an Expected answer the result must contain, an SOA zone for serial convergence, and a per-source Resolver override.
  3. SaveSet the interval and click Add Source. The card shows the success rate across the pool, p95 and max latency, expected-answer mismatches, SOA-serial convergence, and any resolvers with TCP/53 down.
The add-source form with the integration selected and its per-type options loaded.
The add-source form with the integration selected and its per-type options loaded.
The live card on the canvas — latest value, label, and sparkline, updating on the source’s interval.
The live card on the canvas — latest value, label, and sparkline, updating on the source’s interval.

Good to know

  • Resolvers are probed independently and in parallel — one dead server lowers the success rate instead of failing the whole source, so the card tells you which resolver broke.
  • The SOA-serial check compares every resolver’s serial for the zone: a mismatch flags a stale or unconverged secondary before clients start getting old answers.
  • The expected-answer match is a case-insensitive substring over the returned records — enough to pin a VIP or CNAME target without brittle exact matching.

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See it on your own infrastructure

Book a demo and we will walk you through Topologix with your systems in mind: on our cloud, or self-hosted in your own network.

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