Domain and IP bulk lookup tool

GeoIP, ISP, organisation and ASN — for IP addresses and for domain names. Paste a list of up to 100 hosts; we resolve everything we already have on file instantly, and queue the rest for background lookup with a live progress bar on the results page.

Targets (one per line)

One target per line, comma or semicolon. Maximum 100 entries.

Preserve duplicates ⓘ Additional DNS lookup:

Free to use, no signup. On the next page you confirm before we run the check.

What this check returns

IP: The resolved IPv4 address that was actually checked.
Domain: The domain name that was queried.
Country: Country the address is geolocated to.
Region: —
City: City the address is geolocated to (approximate).
ISP: Internet Service Provider that operates the address.
ASN: —

Bulk IP & domain lookup

YouMonit's bulk lookup tool answers one question, fast and at scale: where on the internet does this host live, and who runs it? Paste up to 100 IP addresses or domain names; cached entries appear instantly, the rest are resolved in the background while a live progress bar keeps you updated.

What you get back

For every address or hostname we resolve the IP pair (IPv4 and IPv6 when both exist), the associated domain (via reverse DNS for raw IPs) and the geo/ASN block: country with flag, region, city, ISP and Autonomous System Number. Optionally we also fetch one extra DNS record type per row — MX, NS, TXT, A, AAAA or CNAME — so a single submission can replace a `dig` loop.

Key features

Bulk processing — up to 100 IPs or domains per request, no signup required.
Cache-first lookup — every previously resolved target is served instantly from disk.
Live queue progress — uncached targets are dispatched to the background worker; the page updates as each one resolves.
IPv4, IPv6 and hostnames — one input box for everything; the table shows both addresses for dual-stack hosts.
Optional DNS record — pick MX, NS, TXT, A, AAAA or CNAME from the dropdown to add one extra column per row.
Preserve duplicates — by default duplicate targets are collapsed; tick the box to keep one row per submitted line.
CSV / JSON / YAML / XML export — pull the table straight into your own tooling.
Privacy-respecting — lookups happen over HTTPS, results are protected by reCAPTCHA v3, and we never share lookup data with third parties.

Common use cases

Network security & administration

Identify the origin of suspicious traffic, investigate brute-force sources, and spot anomalies in access logs. Knowing the country, ISP and ASN behind an address turns a raw log line into actionable intel.

Fraud prevention

Compare a customer's billing country with the geolocation of the IP they're paying from. Use ASN to flag traffic coming from hosting providers and known VPN networks instead of residential ISPs.

Marketing & analytics

Understand audience distribution, plan regional campaigns and customise content delivery based on the geographic reality of your traffic — not just the locale set in a browser.

Compliance & geo-blocking

Enforce data-residency rules, regional restrictions and licensing constraints. Useful for streaming, gaming and any service subject to GDPR or sanction lists.

Columns in the result table

IP: Primary address. For dual-stack hosts the second address is shown underneath in grey. Raw-IP submissions also show the paired address from a reverse PTR lookup.
Domain: Hostname. When you submit a raw IP, this is its reverse-DNS (PTR) name when one is configured.
Country: Country of registration, with an inline flag. Country-level accuracy is typically 95–99 %.
Region: Regional subdivision inside the country. Accuracy varies by ISP practices.
City: Approximate; for many ISPs this is their registration city rather than the user's location.
ISP: Company providing internet connectivity for this IP.
ASN: Autonomous System Number — the network operator's unique routing identifier.
MX / NS / TXT / A / AAAA / CNAME: Optional extra column added when you pick a record type from the Additional DNS lookup dropdown. Multiple records are joined with line breaks inside one cell.

How our system works

Cache-first. Every target you submit is checked against our on-disk cache. Cached entries return immediately, with no external API call.
Queue what's missing. Unknown targets are inserted into a background work queue and a live progress bar tracks how many are still pending.
Worker drains the queue. A cron job resolves queued entries against ip-api.com, respecting upstream rate limits, and writes the answer back into the cache.
Annual refresh. Once a year every cached entry is re-queued so the data stays fresh; the refresh load is spread across 365 days, never blocking lookups in flight.

Accuracy and limitations

Geolocation isn't surveillance. A few things to keep in mind:

Mobile/cellular IPs often resolve to the carrier's POP, not the device.
VPN and proxy users show the exit-node location, not their own.
Corporate networks may map to a headquarters location for every employee.
IP blocks can be reassigned — our annual refresh tries to catch this.

Privacy & rate limits

Lookups travel over HTTPS, the form is gated by Google reCAPTCHA v3 against automated abuse, and we don't share or sell lookup data. The free plan respects ip-api.com's documented limits; when we hit them, your targets are queued and resolved within a couple of minutes by the background worker.

Tips for best results

One target per line — IPv4, IPv6, or a hostname.
Invalid entries are flagged in the result table, never silently dropped.
Tick Preserve duplicates when you submit the same target more than once on purpose (e.g. for log-shaped exports).
Pick one record type from Additional DNS lookup to add MX, NS, TXT, A, AAAA or CNAME to every row.
Export to CSV / JSON / YAML / XML straight from the result page.