51nn.net

We performed a comprehensive analysis of 51nn.net on 2026-06-28. The website returned an HTTP 200 status code with a server response time of 4997ms. The page is served over HTTP/2 protocol with Gzip compression enabled, achieving approximately 60.0% size reduction. The total page weight is 112 KB, and the site is served behind a CDN (Content Delivery Network). Warning: The website does not have a valid SSL certificate. Visitors may see security warnings in their browser, and data transmitted to and from this website is not encrypted. The security headers analysis reveals a score of 0/100 (poor). No security headers are configured, which is a significant security concern. However, the site is missing Content-Security-Policy, Strict-Transport-Security (HSTS), X-Frame-Options, X-Content-Type-Options, Referrer-Policy, and Permissions-Policy, which could expose the site and its users to cross-site scripting (XSS), clickjacking, and other web-based attacks. Our technology detection scan identified 3 technologies across 3 categories powering 51nn.net. The detected stack includes Next.js chunks, React, and Matomo. The site uses Next.js as its primary framework (version chunks). The UI is built with React. Based on our comprehensive analysis of domain age, SSL configuration, email authentication, security headers, and blacklist status, 51nn.net receives an overall trust score of 53/100, classified as "Caution Advised".

After conducting a thorough safety and legitimacy analysis, 51nn.net receives a trust score of 53/100, which places it in the "Caution Advised" category. This score is calculated by evaluating multiple factors including SSL certificate validity, domain registration history, email authentication protocols, security header configuration, and blacklist status across major threat intelligence databases. The analysis identified several positive trust signals: a valid HTTPS connection protecting data in transit. Areas of concern include: the absence of a Content-Security-Policy header, which leaves the site more vulnerable to cross-site scripting (XSS) attacks, no X-Frame-Options header, which could allow the site to be embedded in malicious iframes (clickjacking), missing Referrer-Policy, potentially leaking URL information to third parties, the domain's WHOIS information is hidden behind a privacy service, making it harder to verify the owner's identity, and DNSSEC is not enabled, leaving DNS queries vulnerable to spoofing attacks. While these issues don't necessarily indicate malicious intent, they represent areas where the website's security posture could be improved. We checked 51nn.net against 8 major blacklist databases including Google Safe Browsing, Phishtank, Urlhaus, Openphish, Dnsfilter, Spamhaus Dbl, Surbl, and Virustotal. The domain passed all 8 checks with a clean status, meaning it has not been flagged for phishing, malware distribution, spam, or other malicious activities by any of the tested threat intelligence providers.

Our technology detection engine scanned 51nn.net and identified 3 distinct technologies across 3 categories. This analysis is performed by examining HTTP response headers, HTML source code patterns, JavaScript library fingerprints, CSS framework signatures, and DNS records. Framework: Next.js (version chunks) — provides the application framework and routing for 51nn.net. UI Library: React — handles the user interface rendering and component management for 51nn.net. Analytics: Matomo — tracks visitor behavior and provides traffic insights for 51nn.net.

51nn.net delivers its homepage in 4997ms (server response time), which is considered slow by industry standards. The total page weight is 112 KB, and we detected 67 resource requests loading assets from 6 third-party domains. A high number of third-party domains can significantly impact page load time due to additional DNS lookups and TLS handshakes required for each domain. The website uses Gzip compression for text-based assets, achieving an estimated 60.0% reduction in transfer size. This reduces bandwidth usage and improves page load times, especially for visitors on slower connections. Asset minification status: 0 out of 3 CSS files and 0 out of 15 JavaScript files are minified. Minifying the remaining 18 unminified file(s) could further reduce page weight by 10-30% for those assets. Minification is a best practice that reduces download sizes without affecting functionality. The site is served through a Content Delivery Network (CDN), which caches static assets at edge servers around the world. This means visitors from different geographic regions receive content from the nearest edge server, significantly reducing latency. CDN usage is particularly important for websites with a global audience, as it can reduce page load times by 40-60% for distant visitors. From an environmental perspective, each page view of 51nn.net produces approximately 0.05g of CO₂, earning a carbon rating of A. This places the website among the cleanest on the web, demonstrating efficient use of server resources and optimized content delivery. For reference, the average web page produces about 0.5g of CO₂ per page view. The page weight of 112 KB is the primary factor in this calculation. Core Web Vitals data from the Chrome User Experience Report (CrUX) is not available for 51nn.net. This typically means the site doesn't have enough real-world Chrome user traffic to generate statistically significant field data, or the domain is not included in the CrUX dataset. Core Web Vitals (LCP, INP, CLS) are important Google ranking factors that measure real user experience.

51nn.net resolves to the IPv4 address 172.67.199.119 and also supports IPv6 (2606:4700:3034::6815:3cb8), demonstrating modern network infrastructure readiness. The domain has 2 A record(s) configured. The domain name system is managed by 2 name servers: devin.ns.cloudflare.com and melissa.ns.cloudflare.com. Having 2 name servers provides good redundancy — if one fails, the others can continue serving DNS queries. The choice of name servers often indicates the DNS hosting provider or CDN service being used. SPF is not configured, meaning any server could potentially send emails pretending to be from this domain. This is a significant email security concern. DMARC is not configured, leaving the domain vulnerable to email spoofing and phishing attacks that impersonate this domain. DKIM was not detected. Without DKIM, recipients cannot cryptographically verify that emails claiming to be from this domain are authentic. DNSSEC is not enabled for 51nn.net. While not critical for most websites, DNSSEC adds an important security layer by ensuring DNS responses haven't been tampered with during transit. Enabling DNSSEC is recommended for domains handling sensitive data or financial transactions. Our subdomain enumeration scan discovered 1 active subdomains for 51nn.net: www.51nn.net. Active subdomains can reveal the organization's infrastructure, including development environments, API endpoints, and third-party service integrations.

The homepage of 51nn.net contains 47 words of visible text content. This is a relatively short page — adding more descriptive content could improve search engine visibility. The page is structured with 2 H2 headings, 3 H3 headings, 0 H4 headings. The page includes 35 images. 31 images (89%) are missing alt text attributes, which is a significant concern for both accessibility and SEO. Screen readers rely on alt text to describe images to visually impaired users, and search engines use alt text to understand image content. Only 11% of images have proper alt text — we recommend adding descriptive alt attributes to all images. The link structure consists of 0 internal links pointing to other pages on the same domain and 10 external links pointing to third-party websites. There are 15 external JavaScript files, 3 CSS stylesheets, and 0 iframes on the page. The site implements the following web standards and features: XML Sitemap (helps search engines discover all pages) and robots.txt (controls search engine crawling behavior). Notable missing features: Schema.org structured data. Adding these could improve search engine discoverability and rich result eligibility.

The title tag for 51nn.net is good at 21 characters: "皇冠体育软件下载，快速获取最流畅的使用体验". The length is acceptable, though it may be slightly truncated in some search result displays. The meta description is 111 characters (well-optimized): "🔴🟠🟡🟢🔵🟣 访问皇冠体育软件下载，探索高精度智能体脂秤，轻松追踪健康数据，助你保持完美身材。我们的皇冠体育app提供流畅的使用体验，让你随时随地管理体重和体脂，尽享健康生活。选择皇冠体育平台，满足你的健身需求，立即了解！". Google typically displays up to 155-160 characters of the meta description in search results. A compelling meta description with a clear call-to-action can significantly improve click-through rates from search results. The canonical url is correctly set to https://51nn.net, preventing duplicate content issues, the page language is declared as zh-cn, the meta robots directive is set to index, follow, and a favicon is configured. Open Graph meta tags are configured with 3/4 recommended fields: OG title ("皇冠体育软件下载，快速获取最流畅的使用体验..."), OG description, OG type (website). These tags control how the page appears when shared on Facebook, LinkedIn, and other social media platforms that support the Open Graph protocol. A Twitter Card of type summary is configured, which controls how links appear when shared on Twitter/X. The "summary" type displays a large image preview, which typically generates higher engagement rates than the basic card type. The meta keywords tag contains 3 terms including 皇冠体育平台, 皇冠体育app, and 皇冠体育网址. Note: Google has officially confirmed that it does not use the meta keywords tag as a ranking signal. However, some other search engines (Bing, Yandex) may still reference it.