DNS
Nameserver Health Check
Check nameserver health & redundancy
We'll find and check every nameserver for this domain
Try:
github.com
cloudflare.com
google.com
Tool features
4 checks
Server Responsiveness
Test DNS server availability and query response time in real time
DNSSEC Validation
Detect whether DNS Security Extensions are active on each nameserver
Latency Analysis
Measure per-server query response times and surface performance issues
Bulk Server Testing
Check multiple DNS servers simultaneously from a domain or custom list
What is a nameserver health check & how it works
A domain's nameservers answer every DNS query for it, so their health directly determines whether your site and email are reachable. If they're slow, inconsistent, or too few, visitors see timeouts and mail can bounce — even when every individual record is correct.
This check queries each authoritative nameserver directly and measures response time, confirms they agree on the zone's SOA serial, checks DNSSEC status, and looks for enough redundancy across independent servers. You can also switch to the DNS Servers tab to probe a custom list of resolvers.
Redundancy
At least two nameservers on separate networks, so one failure isn’t fatal.
SOA serial
All nameservers should report the same serial — a mismatch means they’re out of sync.
Latency
Query response time; under ~50ms is excellent, over 200ms is a problem.
How to use this tool
1
Choose an input
Use the Domain Name tab to auto-discover a domain’s nameservers, or DNS Servers to probe a custom list.
2
Enter the target
Type a domain, e.g.
example.com, or paste server IPs/hostnames (comma or newline separated).3
Run the health check
Click Start Health Check to query each nameserver for responsiveness, DNSSEC and latency.
4
Review the score
Read the overall grade, per-server cards, grouped diagnostics and recommendations, then export a PDF if needed.
Related tools
5 tools
DNS Servers
Find and test DNS servers for a domain or IP address with performance metrics
Public DNS Speed Test
Compare response times across popular public DNS resolvers like Google, Cloudflare, and Quad9
DNS Lookup
Perform DNS queries for A, AAAA, MX, TXT, CNAME, and other DNS record types
Online Ping
Ping servers to check connectivity and measure response time with detailed statistics
IPv6 Readiness Test
Test whether a domain's website, nameservers and mail servers really work over IPv6, with an IPv4 comparison and fixes
Frequently asked questions
5 Q&A
Yes. Switch to the "DNS Servers" tab and paste IPs or hostnames (comma or newline separated) to run the health check against your own list.
No. The checker is read-only and only sends standard DNS queries to evaluate responsiveness.
The tool queries each nameserver for RRSIG records. A successful response indicates the server is returning DNSSEC-signed data.
Under 50 ms is excellent, 50–100 ms is good, 100–200 ms is acceptable, and above 200 ms indicates a potential performance issue.