ZeroTrace OSINT
ASN Lookup
Autonomous-system number, organisation, prefix list, peering, RIR allocation date, and abuse contact.
The ASN tool looks up an autonomous-system number (or an IP address, in which case the tool resolves the announcing AS first) and returns everything publicly known about the network behind it.
What you get
| Field | What it tells you |
|---|---|
| AS number | The autonomous system number (e.g. AS15169) |
| Organisation | The org name registered with the regional internet registry |
| Country | Country of registration |
| RIR | Regional internet registry (ARIN, RIPE, APNIC, LACNIC, AFRINIC) |
| Allocation date | When the AS was first allocated |
| Announced prefix count | How many CIDR blocks the AS announces in BGP |
| Announced prefixes | The full prefix list, paginated |
| Peer ASNs | Direct BGP peers — who this network exchanges traffic with |
| Upstream providers | Networks that route this AS's traffic to the wider internet |
| Abuse contact | Email parsed from RDAP entities |
When to use it
- Mapping a target's network footprint. A company with one ASN and forty announced prefixes has a much wider attack surface than a company that uses a single hosting provider's ASN.
- Identifying the upstream chain. A small ASN's upstream providers tell you which carriers it depends on — useful for dependency mapping and for noticing oddball routing (a European company routing through a Russian carrier, for example).
- Finding co-located infrastructure. Two domains on different CIDRs but the same ASN are operated on the same network — often the same business.
- Picking the right abuse contact. RDAP entities frequently include role-based abuse emails that a public-website-only search misses.
Announced prefix list
The full BGP prefix list is paginated (some networks announce thousands of prefixes). Each prefix shows:
- The CIDR block.
- A pivot to reverse DNS (run as a bulk against the expanded range — tag-team with CIDR tools).
- A pivot to exposed services for the prefix.
Peer / upstream graph
The peer and upstream lists are derived from public BGP data. They tell you:
- Who this network talks to directly. Peers exchange traffic without paying each other.
- Who provides transit. Upstreams route this network's traffic to the wider internet, usually for a fee.
A network with no peers and many upstreams is a customer of those upstreams. A network with many peers is a major operator in its own right.
For supply-chain reconnaissance against a SaaS vendor, the ASN's upstream providers are often more interesting than the SaaS vendor themselves. A SaaS that single-homes through one upstream has a different reliability profile than one that multi-homes across three carriers.
Looking up by IP vs. by ASN
Both inputs work:
- Paste an AS number (
15169,AS15169,as15169) and the tool returns the full record. - Paste an IP address and the tool resolves to the announcing AS first, then returns the same record.
Pivots
| Click on... | Pivot to |
|---|---|
| A peer ASN | ASN lookup (recursive) |
| An upstream ASN | ASN lookup (recursive) |
| An announced prefix | CIDR tools (range expander), then bulk-paste to reverse DNS |
| Abuse email | Email analyzer |
| Organisation name | (no pivot — copy and paste) |
Sources
- BGPView for ASN metadata, prefixes, peers, upstreams.
- RDAP for the registry-side org and abuse-contact details.
- "View on bgp.he.net" affordance for cases where you want to see Hurricane Electric's view of the same data.
Every source is named on the result.