International Journal of Web Applications Ramiro Sámano Robles 18 3 2026 https://doi.org/10.6025/ijwa/2026/18/3/125-144 https://www.dline.info/ijwa/fulltext/v18n3/ijwav18n3_1.pdf The Domain Name System (DNS) is a critical foundation of internet functionality, yet its reliability remains vulnerable to physical, logical, and operational failures. While substantial research exists on DNS security and topology, large scale assessments of country code top level domains (ccTLDs) remain limited. This study presents a comprehensive empirical analysis of DNS reliability and web reachability within the German .de domain ecosystem. Utilizing a stratified 10% random sample (N = 636,853) from a verified inventory of 6.38 million. de domains (derived from Common Crawl data spanning 2019-2026), we evaluated sequential DNS resolution and HTTP/HTTPS accessibility. Descriptive and inferential statistical methods, along with a novel DNS Reliability Index (DRI), were used to quantify operational health. Results indicate a DNS resolution rate of 66.24% (95% CI [66.12%, 66.37%]), but a significant attrition to full web reachability, with only 35.42% of the total sample (or ~42.2% of actively checked domains) returning successful HTTP 200 responses. DNS failures (ERR_DNS, 28.36%) and network timeouts (ERR_TIMEOUT, 11.94%) emerged as the primary barriers to accessibility. The DRI remained stable (~66.2%) across domain name lengths, though temporal anomalies highlighted batch specific probing effects. These findings Shown that domain registration does not guarantee service availability, highlighting the need for continuous monitoring and improved registration maintenance to enhance the resilience of the web ecosystem.