BGP Autonomous System Number (ASN) Guide
BGP Autonomous System Number (ASN) Guide: shows fixed RFC private-use, documentation, and reserved ranges; it does not query BGP, RIR, or IANA.
About this bgp autonomous system number (asn) guide
BGP Autonomous System Number (ASN) Guide — browser-based utility.
How this tool works
Implements client-side BGP Autonomous System Number (ASN) Guide operations. Shows fixed RFC private-use, documentation, and reserved ASN ranges; it does not query BGP, an RIR, or IANA allocation data.
- URL & Header Semantic Parsing: Ingests raw URLs or Cache-Control header tokens, validating syntax against RFC 3986/9110 specifications.
- Cache-Hierarchy Evaluation: Models browser cache vs CDN shared cache behaviors (evaluating max-age vs s-maxage and revalidation flags).
- Port & Protocol Lookup: Matches numeric ports to standard IANA assignments (e.g. 443 for HTTPS, 22 for SSH, 53 for DNS, 3306 for MySQL).
- Diagnostic Reporting: Visualizes cache expiration timelines and highlights conflicting caching headers (such as no-store combined with max-age).
Worked example
Scenario: Read the local reference object for ASN 64512.
Sample input:
Processing: Trim the query and return the fixed private, documentation and reserved ASN ranges.
Illustrative output:
Limits and verification
Flags contradictory caching directives (e.g. combining 'no-store' with any 'max-age' value). URL parser strictly enforces valid URI schemes and flags invalid percent-encoded characters.
Examples demonstrate an expected workflow; they do not prove every input or every branch of an external specification. Check important results with an independent source before using them for money, security, compliance, safety, or irreversible file changes.
Browser processing boundary
Tool input is processed by code running in the browser and is not intentionally sent to a CZOA processing API. The page can still request ordinary site assets, analytics, or advertising when those services are enabled. Browser extensions and managed-device software remain outside this tool's control.
Relevant references
These references govern or help explain the format, protocol, or calculation used here. Listing a reference does not claim certification or complete implementation of every optional feature.
Content owner: CZOA Tools · Last reviewed: 2026-09-15 · Review methodology
How to use it
- Enter, paste, or select your input data into the BGP Autonomous System Number (ASN) Guide workspace controls.
- Review available parameter fields, units, formats, or options configured for your task.
- Click the action button or observe immediate live calculations rendered in your browser runtime.
- Inspect the resulting output and any diagnostic messages, then copy or download the result if needed.
Frequently asked questions
What ranges does this guide return?+
It returns a fixed reference object: private-use ASN ranges 64512-65534 and 4200000000-4294967294, documentation ranges 64496-64511 and 65536-65551, and reserved values 0, 23456, 65535 and 4294967295. Those literal ranges are not calculated from the entered ASN.
What does the page actually do?+
The page has one text area, Run locally and Load sample. It trims the submitted text into query, then displays JSON containing the same fixed ranges, RFC 6996, RFC 5398 and RFC 7300, and a scope note. It does not establish BGP sessions, inspect routes, query an RIR, or consult a live registry.
What are its input and accuracy boundaries?+
Any text is accepted after trimming and is only echoed as query; there is no numeric ASN parser, range membership result, RIR ownership check, route-origin lookup, prefix analysis, or current allocation data. The displayed standards are fixed reference labels, so use an authoritative current registry for an operational assignment decision.
What did the isolated browser check show?+
For query 64512, the isolated browser returned the fixed reference object with both private-use ranges, both documentation ranges, four reserved values, the three RFC labels, and the no-live-query note. This checks that local fixed-object path only; it does not establish BGP reachability, RIR freshness, or ASN ownership.