--- title: Kto i dlaczego losuje w Polsce rozkład jazdy PKP | daily.dev description: A Polish railway passenger portal (Portal Pasażera) displays randomized train schedules to certain users based on their IP addresses. Technical investigation... canonical: https://daily.dev/posts/hqa36mwzo twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: Kto i dlaczego losuje w Polsce rozkład jazdy PKP | daily.dev og:description: A Polish railway passenger portal (Portal Pasażera) displays randomized train schedules to certain users based on their IP addresses. Technical investigation... og:url: https://daily.dev/posts/hqa36mwzo og:image: https://api.daily.dev/og/posts/hQA36mWZO.png og:image:alt: Post cover image og:image:width: 1200 og:image:height: 630 og:locale: en --- > ## Documentation Index > Fetch the complete documentation index at: https://daily.dev/llms.txt > Use this file to discover all available pages before exploring further. # Kto i dlaczego losuje w Polsce rozkład jazdy PKP **[Paweł Kraszewski](https://daily.dev/sources/jnzbj0vldwcbkgbvjvwx4)** · [@pkraszewski](https://daily.dev/pkraszewski) · 0 upvotes · 0 comments ## Summary A Polish railway passenger portal (Portal Pasażera) displays randomized train schedules to certain users based on their IP addresses. Technical investigation revealed the system returns departure times with uniform random distribution of ±60 minutes when accessed from specific mobile networks (CGNAT addresses), likely as an anti-scraping measure. The randomization affects legitimate users sharing IP addresses with suspected bots. Analysis of 3000 requests confirmed purely random errors that average to correct times, with SSL/TLS properly configured ruling out MITM attacks. PKP declined to comment citing security reasons. ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: ## Similar posts on daily.dev - [Security researchers scanned the Polish web and found courts, hospitals, and airports at risk of hacks](https://daily.dev/posts/security-researchers-scanned-the-polish-web-and-found-courts-hospitals-and-airports-at-risk-of-hac-evhbbtunt) · TechCrunch · 0 upvotes · 0 comments - [In a Weird Case, German Deutsche Bahn's Website Was Locking Out Linux Users](https://daily.dev/posts/in-a-weird-case-german-deutsche-bahn-s-website-was-locking-out-linux-users-e5jzenzjh) · It's Foss · 3 upvotes · 1 comments - [A student with a laptop and a radio stopped four high-speed trains. The crypto keys hadn’t been changed in 19 years.](https://daily.dev/posts/a-student-with-a-laptop-and-a-radio-stopped-four-high-speed-trains-the-crypto-keys-hadn-t-been-chan-d6etxlem2) · The Next Web · 0 upvotes · 0 comments - [live public transport routing](https://daily.dev/posts/live-public-transport-routing-bwp2hvdsm) · Hacker News · 0 upvotes · 0 comments --- Tags: [#cyber](https://daily.dev/tags/cyber), [#crawling](https://daily.dev/tags/crawling) [View this post on daily.dev](https://daily.dev/posts/hqa36mwzo) ```json {"@context":"https://schema.org","@graph":[{"@type":"Organization","@id":"https://daily.dev/#organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180},"sameAs":["https://twitter.com/dailydotdev","https://github.com/dailydotdev","https://www.linkedin.com/company/daily-dev-ltd"]},{"@type":"WebSite","@id":"https://daily.dev/#website","url":"https://daily.dev","name":"daily.dev","publisher":{"@id":"https://daily.dev/#organization"},"potentialAction":{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https://daily.dev/search?q={search_term_string}"},"query-input":"required name=search_term_string"}}]} {"@context":"https://schema.org","@type":"DiscussionForumPosting","mainEntityOfPage":"https://daily.dev/posts/hqa36mwzo","headline":"Kto i dlaczego losuje w Polsce rozkład jazdy PKP","text":"Shared: Kto i dlaczego losuje w Polsce rozkład jazdy PKP","url":"https://daily.dev/posts/hqa36mwzo","datePublished":"2026-02-04T06:29:07.687Z","dateModified":"2026-02-04T06:29:53.676Z","author":{"@type":"Person","name":"Paweł Kraszewski","url":"https://daily.dev/pkraszewski","image":"https://avatars.githubusercontent.com/u/1206223?v=4","description":"Gets shit done with Erlang, Go and Rust on Linux and FreeBSD. 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