Bulk Domain Checks: DNS, SSL and WHOIS for a Whole Portfolio at Once
Anyone managing more than a handful of domains eventually faces the batch problem: renewals scattered across years, certificates expiring at different times, DNS hosted in three places after two acquisitions. Checking domains one by one guarantees that at least one expiry will be missed, because the process depends on memory. Bulk checking replaces memory with a table.
What a batch run covers
- DNS: whether the domain resolves at all, its A/AAAA records, NS delegation, and MX presence — enough to spot dead delegations and misconfigured records across a portfolio.
- SSL/TLS: for each HTTPS host, the certificate’s issuer, validity window and days remaining. A certificate expiring in 4 days across a portfolio of 80 domains is exactly the finding a one-by-one process misses.
- WHOIS: registrar, expiry date and status codes for the domain itself. Domain expiry causes more outages than certificate expiry and is far less automatable, since registrars differ.
Workflows this unlocks
- Expiry sweeps: sort the results by days-remaining and you have the renewal list for the quarter — certificates and domains in one view.
- Pre-migration inventory: before consolidating hosting or DNS, run the full list to capture what currently resolves where. The export becomes your rollback reference: every record documented before anyone touches a nameserver.
- Post-migration verification: re-run the same list after the change and diff. Any domain that stopped resolving, lost its certificate or kept a stale A record appears immediately instead of surfacing through user complaints over two weeks.
- Acquisition and due-diligence triage: a fresh portfolio audit answers “what did we just inherit?” — expiring registrations, expired certificates, nameservers still pointing at the previous owner.
The CSV workflow
The practical loop with any batch tool:
cut -d, -f1 client-domains.csv | head -100 # columns: domain,owner,notes — keep one canonical list, re-run it monthly
Feed the domain column to the batch checker, export the results as CSV, and diff against last month’s export. Keep the list in version control if you can; the history of the list itself is useful. Batch tools process domains in chunks over AJAX precisely so a 100-domain run does not time out — expect the full sweep to take minutes, not seconds, and let it run.
Two limits to respect: batch checks hit public services (WHOIS servers rate-limit aggressively), so 100 is a sensible ceiling per run rather than an arbitrary one; and results reflect the moment of the check — a clean sweep is a snapshot, which is why the monthly cadence matters more than any single run.
The bulk domain checker on WhoDNS runs DNS, SSL and WHOIS across up to 100 domains with chunked processing, colour-coded results and CSV upload/export — the entire portfolio audit in one screen, with the export serving as next month’s baseline.