loading
Loading content
loading
Network
Get the announced IP prefixes for an autonomous system number.
overview
get-asn-prefixes resolves a single autonomous system number into the list of IP prefixes that ASN announces. Give it an ASN such as AS64496 and it returns the CIDR blocks routed under that number, turning a network identity into concrete address space you can scan and probe.
Those prefixes seed infrastructure mapping. Once you know which CIDRs an ASN owns, you can expand them to individual hosts, port-scan the live ones, and probe the services that answer. The node keeps its input narrow: one ASN in, the prefixes out.
In a Trickest workflow get-asn-prefixes takes one ASN and writes a folder and a file of prefixes. It sits at the front of an infrastructure-mapping workflow, ahead of CIDR expansion and scanning, and pairs well with an ASN lookup step that produces the number first.
source github.com/trickest
use cases
Resolve a known ASN to the CIDR prefixes routed behind it, then treat those ranges as the in-scope boundary for the rest of the engagement.
Write the prefixes to a file and hand them to a CIDR expander and a port scanner so probing runs against the IP space the ASN announces.
Start from the ASN you resolved for a company and pull its prefixes to reveal the broader network it operates, including ranges no published hostname points at.
Run it per ASN across an organization's autonomous systems and collect the prefix files into a single picture of the address space it controls.
reference
| Name | Type | Flag | Description |
|---|---|---|---|
| asn | STRING | · | Autonomous system number to fetch announced IP prefixes for (passed positionally, for example AS64496). |
Showing key inputs. get-asn-prefixes exposes 1 inputs in total.
example
# get-asn-prefixes: list announced CIDRs for one ASNget-asn-prefixes AS64496192.0.2.0/24198.51.100.0/24198.51.100.0/25198.51.100.128/25203.0.113.0/24203.0.113.0/26203.0.113.64/26203.0.113.128/25guidance
Reach for get-asn-prefixes when you already have an ASN and need the prefixes it announces. To resolve an org, domain, or IP to an ASN first, run asnmap. To slice or merge the prefixes once you have them, use mapcidr.
Resolves an org, domain, ASN, or IP to ranges. Run it ahead of this node when you only have a name, not a number.
Operates on CIDR ranges (split, merge, aggregate). Use it after this node to reshape the prefixes.
Expands CIDR ranges into individual IP addresses. Run it on the prefixes before host-level scanning.
faq
related
Quickly map an organization's network ranges using ASN information.
Maximize your resolver count by combining the target's DNS servers with public resolvers.
Expand CIDR ranges into a list of IP addresses easily.
Expand CIDR ranges into a list of IP addresses easily, from a file.
Maintain a list of IPv4 DNS servers verified against baseline servers for accurate responses.
Patched dnsvalidator that keeps only IPv4 resolvers verified against baseline servers.
An ASN feeds get-asn-prefixes, which pulls the announced CIDR blocks and passes them to mapcidr for cleanup before they land as a queryable prefixes output.
Facts on this page come from the live Trickest tool library.