Understand domain registration and nameserver checks
Read daily RDAP or WHOIS details and registration-change incidents.
Last checked 20 August 2026
The Domain Validation Checks card shows registration details for the registrable domain, not necessarily the full monitored hostname. For shop.example.co.uk, for example, the lookup is performed for the registrable domain rather than the shop subdomain.
The card can show:
- Registrar
- Reseller, when supplied
- Valid From
- Expires On
- Days Remaining
- Last Updated
- Nameservers
Missing fields display -. Some registries do not publish an expiry date, registrar, or reseller, so a blank field is not automatically a domain fault.
How the lookup works
TechDash uses IANA's RDAP bootstrap data to choose the registration service for the domain. It caches a valid bootstrap response for 24 hours. When RDAP is unavailable, returns an error, or is not available for the suffix, TechDash falls back to WHOIS.
RDAP and WHOIS responses vary considerably. TechDash normalizes parseable dates and converts nameservers to lowercase, removes trailing dots and duplicates, rejects IP-address-only values, and sorts the resulting hostnames. This normalization prevents casing and ordering changes from opening false incidents.
Domain lookups become due 24 hours after the last attempt. The lookup scheduler reviews due websites every hour while monitoring is active. The actual run can be later when the app is closed, the computer is offline or asleep, the license is unavailable, the website is paused, or another Domain queue job is ahead.
A successful lookup replaces the stored details. A failed lookup retains the prior fields, records the error and checked time, and does not evaluate registrar or nameserver changes from incomplete data.
Read domain expiry
When a public expiry date exists, TechDash calculates whole days remaining and colors Expires On and Days Remaining:
- 30 days remaining is normal.
- 29 through 7 days remaining is Warning.
- 6 days or fewer is Critical.
The incident title is Domain expiring soon. It can be created on the first successful observation because expiry is an absolute current state, not a change from a previous registrar lookup. A Warning can notify once and then notify again if it escalates to Critical.
Confirm renewal in the registrar account rather than relying only on public RDAP or WHOIS. Public expiry fields can be omitted, delayed, or interpreted differently during auto-renew grace periods. Check billing status, auto-renew settings, payment method, account email, registry lock, and the actual registrable domain.
Read nameserver and registrar changes
The first non-empty successful value establishes a baseline and does not open an incident.
On later successful lookups:
- Nameservers changed is Warning when both the previous and current normalized sets are non-empty and differ.
- Registrar changed is Warning when both the previous and current registrar names are non-empty and differ.
The incident evidence shows the previous value as Expected and the new value as Current. A missing value does not count as a change. This avoids treating temporary registry omissions as a confirmed transfer or DNS cutover.
A change can be legitimate:
- Planned DNS provider migration
- Registrar transfer
- Managed DNS failover
- Registry or reseller naming update
It can also indicate an unauthorized account or domain change. Confirm the change with the domain owner and registrar, then verify DNS resolution, website responses, email routing, and TLS on the production hostname.
Troubleshoot unexpected data
If the card is pending, wait for the Domain queue. If it shows a lookup error, check internet connectivity, RDAP or WHOIS reachability from this computer, local firewall or VPN policy, and whether the registry rate-limited requests.
If nameservers look incomplete, compare:
- The registrar account
- Registry RDAP
- Authoritative delegation from the parent zone
- The actual NS records returned for the domain
These sources can disagree briefly during a cutover. TechDash reports registration data, while Hostname resolution separately tests whether the monitored hostname resolves.
Use Check & Verify from a domain incident to run RDAP/WHOIS immediately and refresh the incident. Check now in Site Resources does not run the domain lookup. Without a manual incident recheck, wait for the next daily due time and hourly scheduler sweep.