computer science

Prefix WhoIs

Prefix WhoIs is a computer science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Prefix WhoIs rather than just read about it. In short: Prefix WhoIs is an open source project that develops and operates a free whois-compatible framework for stockpiling and querying various routing and registry information. Prefix WhoIs uses global BGP routing data learned from many ISP backbone routers.

Key takeaways

Prefix WhoIs belongs to computer science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Prefix WhoIs to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Prefix WhoIs from memory before moving on to harder problems.

Reference excerpt

Prefix WhoIs is an open source project that develops and operates a free whois-compatible framework for stockpiling and querying various routing and registry information. Prefix WhoIs uses global BGP routing data learned from many ISP backbone routers. Other information sources are also supported, such as imported data from every regional Internet registry (AFRINIC, APNIC, ARIN, LACNIC, and RIPE) and geocoding information. The project has been mentioned in a number of popular network security and network engineering books and articles.

Public Prefix WhoIs Service Many public servers around the world operate mirrors of Prefix WhoIs, making the information generally available worldwide. The service may be used with any client using the standard whois protocol. The DNS address whois.pwhois.org resolves to the Prefix WhoIs server nearest to the client based on anycast DNS.

Client Software Several client software packages are available from both Prefix WhoIs itself and from commercial vendors. These include free, open source utilities such as WhoB and Layer Four Traceroute.

Server Software The pWhoIsd server software responds to standard whois queries and supports a variety of output formats (including Prefix WhoIs native, Cymru, and RPSL). The pWhoIs-updatedb agent parses routing information bases (RIBs) from Internet routers or digests from route-views servers in text or MRT format and populates a relational database

Software Development Libraries The Prefix WhoIs project distributes C and PHP libraries for direct access to Prefix WhoIs servers. A HTTP simpleQuery interface is also available.

Software licensing The software is made available under a custom license.

Sources

External links The Prefix WhoIs Project Official Web Site

Illustrations

Worked examples

Example 1 — a first encounter with Prefix WhoIs

Start with the simplest possible case. Write down what Prefix WhoIs claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In computer science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Prefix WhoIs before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Prefix WhoIs ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Prefix WhoIs

In research: Prefix WhoIs appears in computer science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Prefix WhoIs in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Prefix WhoIs is common in secondary-school and first-year university syllabi. It links to neighbouring topics Free network management software, Network analyzers, so understanding it makes those chapters shorter.
In everyday life: Look for Prefix WhoIs outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Prefix WhoIs in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Prefix WhoIs means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Prefix WhoIs out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Prefix WhoIs in simple terms?

Why does Prefix WhoIs matter?

Because it connects several computer science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Prefix WhoIs?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Prefix WhoIs.