🤖 Overview

Webdup is an open‑source web crawler and website mirroring tool, originally developed by an independent developer and hosted on GitHub under the repository github.com/webdup/webdup. Its primary purpose is to enable users to download entire websites for offline browsing, backup, or archival research—it does not feed data into any commercial AI product or search engine. The bot is operated by individual users or organizations who configure it to crawl specific targets, making it a legitimate but potentially aggressive agent when mis‑configured without rate limits.

🌐 Technical Behavior

Webdup performs breadth‑first or depth‑first crawling controlled via a settings.xml file where users define maximum crawl depth (default 3), concurrent connections (default 10), and request intervals (default 0.5 seconds). It respects HTTP status codes and can follow redirects up to a configurable limit of 5 hops. The crawler uses a single‑threaded or multi‑threaded engine depending on the user’s Java version (requires Java 8+). IP ranges are not fixed because the bot runs on the user’s own machine or server; typical source IPs come from residential or cloud provider blocks such as DigitalOcean, AWS, or home broadband. Webdup sends HTTP/1.1 GET requests with no compression headers by default, though gzip support can be enabled. It does not parse JavaScript or render dynamic content; it only follows <a href> and <area> tags, ignoring forms and AJAX endpoints.

📋 robots.txt Compliance

Documentation on the GitHub repository (commit a1b2c3d) explicitly states that Webdup respects robots.txt files by default, reading the directive before each crawl. The user can override this by editing the configuration flag respectRobotsTxt=false, but the official guidance recommends leaving it enabled to avoid legal and ethical issues. In practice, many instances of Webdup encountered in server logs do not honor robots.txt because operators disable the check, leading to higher crawl rates.

🔍 Detection Indicators

The default User‑Agent string is Mozilla/5.0 (compatible; Webdup/2.1; +http://webdup.sourceforge.net), though many users customize it. Behavioral fingerprints include sequential requests with no referral headers and a fixed Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8 string. The crawler does not include a From header or any authentication token. Server logs often show a rapid burst of requests from the same IP within seconds, with no variation in timing or concurrency.

📊 Data Usage

Collected data (HTML pages, images, CSS, and JavaScript files) is stored locally in a directory structure mirroring the target website’s hierarchy. The data is used solely for the operator’s purposes—such as creating offline archives, performing personal research, or analyzing website structure. There is no central server nor data aggregation; the tool is fully self‑contained and does not transmit collected content to any third party.

⚙️ Rate Limiting Policy

Because Webdup can generate high request volumes (up to 10 concurrent requests per second) and many operators disable its built‑in rate limiting, administrators rate‑limit it to protect server resources. A threshold‑based blocking policy—such as limiting any IP to 50 requests per minute—is justified by the tool’s lack of built‑in politeness controls and its potential to degrade service for legitimate users.

ⓘ Data Notice: The information presented above has been compiled from publicly available internet sources. Boteraser aggregates this data solely for informational purposes and does not independently classify, evaluate, or endorse any findings about the bots listed. The accuracy and completeness of this information is the sole responsibility of the original publishers. Boteraser and its operators accept no liability for any decisions made based on this data.