nslookup Connection Diagnostic Tool
Diagnose name resolution by querying multiple DNS servers simultaneously
Features
Simultaneous queries to 4 public DNS servers
Parallel queries to 4 popular public DNS servers
nslookup and dig format output
Copy command output in either nslookup or dig format
Automatic response consistency check
Display whether responses match across all servers
Support for 7 record types
Switch between A, AAAA, CNAME, MX, NS, TXT, and SOA records
How to Use
Enter a domain name
Type the domain name you want to diagnose in the input field
Select record type and query servers
Choose the record type to query and adjust which DNS servers to check
Run diagnosis and compare results
Check server responses, response times, and consistency status from the diagnostic results
Copy command output
Use the copy button to get nslookup or dig format text
Use Cases
Verify DNS propagation after changes
Compare whether each DNS server returns the new value after server migration
Troubleshoot connection issues
Verify name resolution when a website won't load
Diagnose in environments without command line access
Run nslookup-equivalent diagnostics from corporate PCs or smartphones
Attach diagnostic results to incident reports
Copy and share command output format text
Knowledge Base
Difference between nslookup and dig
Both nslookup and dig are commands that query DNS for name resolution, but they differ in output format and the amount of information available.
- nslookup：nslookup displays the responding DNS server and resolution result in a concise format spanning a few lines, making it suitable for checking just IP addresses.
- dig：dig displays responses organized into sections like QUESTION SECTION and ANSWER SECTION, allowing you to read even the remaining TTL seconds.
Why DNS server results differ
Caching DNS servers retain responses for the number of seconds specified by TTL, so immediately after a configuration change, some servers may return old values while others return new values.
- TTL：TTL specifies the number of seconds a record can be cached; if it's 300, the same response will be reused for 5 minutes.
- Time until responses match：Old responses remain until the previous TTL expires, so if TTL is set to 3600, there can be differences of up to about 1 hour.
Interpreting failed responses
When name resolution fails, the next troubleshooting step depends on whether the domain doesn't exist or just the specific record type isn't configured.
- Record not found：The domain name is likely misspelled or the record type is not configured; you can narrow it down by switching the record type.
- Only some servers fail：If only a specific DNS server doesn't respond, it may be due to temporary issues with that server or its cache state.
Security and Privacy
Server-side processing
Input is processed on the server; only information necessary for the inquiry is sent.
Temporary processing only
For DNS query, temporary processing occurs on the server, then data is discarded after results are returned.
Communications encrypted with HTTPS
All sent and received data is encrypted by TLS and cannot be read by third parties.
No transmission to third parties
Input content is not sent to external services such as ad networks or trackers.
Sent only to DNS servers
The domain name you enter is sent only to the selected DNS servers for name resolution.
Updates
- update #230
Added nslookup DNS diagnostic tool
Enter a domain name to simultaneously query Google, Cloudflare, Quad9, and OpenDNS, then compare their responses and response times. You can also copy output in nslookup and dig command style.