How to find a TLD WHOIS server

A TLD WHOIS server lookup identifies the registry host that can answer for names under a top-level domain before a second-level domain query moves to registration details. Starting from IANA prevents a copied server list or default client from sending evidence to a stale or unrelated registry.

IANA's WHOIS service accepts top-level domain labels on port 43 and returns the root-zone delegation record. A non-empty whois: field is the legacy registry WHOIS server; the nserver: lines describe TLD delegation and do not prove the authoritative DNS for a domain under that TLD.

Some TLDs do not publish a legacy WHOIS endpoint. A blank whois: field or a missing TLD record means the evidence should name that absence and move to the registry web or RDAP path instead of guessing a server.

Steps to find a TLD WHOIS server:

Query IANA for the top-level domain label.

$ whois -h whois.iana.org -p 43 com
% IANA WHOIS server
% This query returned 1 object

domain:       COM

organisation: VeriSign Global Registry Services
##### snipped #####
whois:        whois.verisign-grs.com

status:       ACTIVE
source:       IANA

Use the TLD label without the leading dot. The -p 43 option keeps the WHOIS port explicit for clients that do not map the default service name.

Confirm that the IANA record matches the TLD being checked.
```
domain:       COM
source:       IANA
```
A TLD record identifies the registry layer for names under that top-level domain. It is not the registration record for example.com or any other second-level domain.
Copy the non-empty whois: field as the TLD registry WHOIS server.
```
whois:        whois.verisign-grs.com
```
Related: How to select a whois server
Treat a blank whois: field as no published legacy WHOIS server.
```
$ whois -h whois.iana.org -p 43 mil
% IANA WHOIS server
% This query returned 1 object

domain:       MIL
##### snipped #####
whois:

status:       ACTIVE
source:       IANA
```
Do not invent likely hostnames such as whois.<tld> when IANA does not publish a server. Use the registry information, RDAP, or the page's required evidence path instead.

Related: How to query RDAP for a domain

Query the selected TLD server for a domain in that zone when domain-level evidence is needed.

$ whois -h whois.verisign-grs.com example.com
   Domain Name: EXAMPLE.COM
   Registry Domain ID: 2336799_DOMAIN_COM-VRSN
   Registrar WHOIS Server: whois.iana.org
   Updated Date: 2026-01-16T18:26:50Z
   Creation Date: 1995-08-14T04:00:00Z
   Registry Expiry Date: 2026-08-13T04:00:00Z
##### snipped #####

Save the IANA record when server choice must be attached to a ticket or handoff.
```
$ whois -h whois.iana.org -p 43 com > com.iana.whois
```
Related: How to save raw whois output
Record the server and selection source with the saved evidence.
```
TLD: com
Selection source: IANA WHOIS record
TLD WHOIS server: whois.verisign-grs.com
Evidence file: com.iana.whois
```
The check is complete when the saved IANA record names a non-empty TLD WHOIS server that answers for an in-zone domain, or when the saved record proves that IANA does not publish a legacy WHOIS server for that TLD.