Google 公用 DNS 簡介
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選擇 Google 公用 DNS 的理由
隨著網頁日趨複雜，並包含來自多個來源網域的更多資源，用戶端需要執行多項 DNS 查詢才能轉譯單一網頁。一般網際網路使用者每天會執行數百筆 DNS 查詢，拖慢了他們的瀏覽體驗。隨著網路持續發展，更多的負載會投入現有的 DNS 基礎架構。
由於 Google 的搜尋引擎每天都會檢索網路，且過程中會解析及快取 DNS 資訊，因此我們希望利用我們的技術進行實驗，嘗試以新方式解決一些與效能和安全性相關的現有 DNS 難題。我們會為大眾提供這項服務，希望達成以下目標：
- 為使用者提供目前的 DNS 服務替代方案。Google 公用 DNS 採用一些新方法，我們認為可提供更有效的結果、提升安全性，在大多數情況下，效能也更佳。
- 協助降低網際網路服務供應商 (ISP) DNS 伺服器的負載。
借助我們全球資料中心和快取基礎架構，我們可以直接提供大量使用者要求，而不必查詢其他 DNS 解析器。
- 讓網站更快速安全。
我們推出這項服務，是測試一些因應 DNS 相關挑戰的新方式。我們希望與 DNS 解析器和更廣大的網路社群的開發人員分享我們學到的經驗。
Google 公用 DNS：說明
Google 公用 DNS 是遞迴的 DNS 解析器，類似其他公開可用服務。我們認為這個 API 具備許多優點，包括更高的安全性、更快速的效能，以及更有效的結果。以下是我們實作的技術改善項目總覽。
不過，Google 公用 DNS 沒有下列任何一種：
- 頂層網域 (TLD) 名稱服務。
- DNS 託管或容錯移轉服務。Google 公用 DNS 並非代管其他網域的權威記錄的第三方 DNS 應用程式服務供應商。如果您需要使用 Google 基礎架構尋找大量且可程式化的權威名稱伺服器，請嘗試使用 Google 的 Cloud DNS。
- 權威名稱服務。Google 公用 DNS 伺服器並非任何網域的權威人士，Google 有一組註冊網域且具有權威性的名稱伺服器，由 ns[1-4].google.com 代管。
- 惡意軟體封鎖服務。Google 公用 DNS 很少執行封鎖或篩選作業，但如果我們認為有必要採取這個做法來保護使用者免於安全威脅或法律規定，我們可能還是會執行封鎖或篩選作業。在這類極為特殊的情況下，無法回答；並不會產生修改的結果。
優點和改善項目總覽
Google 公用 DNS 提供多種安全性、效能和法規遵循方面的改善。以下提供這些強化功能的簡要總覽。
如果您是 DNS 軟體的開發人員或部署人員，建議您也閱讀這個網站的技術資訊頁面，進一步瞭解這些功能。最終，我們希望分享我們的見解，並激勵社群在所有 DNS 解析器中採用其中幾項功能。
這些變更會分為 3 類：
許多 DNS 服務供應商的佈建不足，無法支援大量的輸入/輸出和快取，且必須充分平衡其伺服器之間的負載。Google 公用 DNS 會使用 Google 規模的大型快取，並平衡使用者流量，藉此確保共用快取，讓我們能回應來自快取的大量查詢。
詳情請參閱「效能優勢」頁面。
安全性
DNS 容易遭受各種假冒攻擊，這些攻擊會「植入」名稱伺服器的快取，並將使用者導向惡意網站。
DNS 漏洞攻擊的盛行，意味著供應商必須經常套用伺服器更新和修補程式。
此外，開放式 DNS 解析器很容易被用來在其他系統上發動阻斷服務 (DoS) 攻擊。為了防範這類攻擊，Google 實作了幾項建議解決方案，確保從其他名稱伺服器收到的回應真實性，並確保我們的伺服器不會用於啟動 DoS 攻擊。除了完整支援 DNSSEC 通訊協定之外，其中包括在要求中加入熵、頻率限制用戶端流量等。
此外，如果 Google 認為這是為了保護 Google 使用者免受安全威脅的必要措施，Google 公用 DNS 可能不會解析特定網域。
詳情請參閱「安全性優點」頁面。
正確性
Google 公用 DNS 會盡可能根據 DNS 標準，在每次查詢時傳回正確的答案。有時候，在查詢的網域名稱輸入錯誤或不存在時，正確答案表示沒有答案，或者顯示無法解析網域名稱的錯誤訊息。此外，如果我們相信這是保護使用者免於安全威脅的必要措施，也可能不會解析特定網域。
與某些開放解析器和網際網路服務供應商 (ISP) 不同，Google 公開 DNS 絕不會將使用者重新導向。
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上次更新時間：2025-07-25 (世界標準時間)。
[null,null,["上次更新時間：2025-07-25 (世界標準時間)。"],[[["\u003cp\u003eGoogle Public DNS is a free, publicly available recursive DNS resolver offered by Google to enhance internet speed, security, and result accuracy.\u003c/p\u003e\n"],["\u003cp\u003eGoogle Public DNS leverages Google's vast infrastructure to provide faster responses by caching DNS information and efficiently balancing user traffic.\u003c/p\u003e\n"],["\u003cp\u003eIt implements security measures to protect against DNS spoofing and denial-of-service attacks, prioritizing user safety.\u003c/p\u003e\n"],["\u003cp\u003eGoogle Public DNS strives to return valid results while adhering to DNS standards; however, it may not resolve certain domains for security reasons.\u003c/p\u003e\n"],["\u003cp\u003eThis service is not a DNS hosting service, a top-level domain service, or a malware-blocking service.\u003c/p\u003e\n"]]],["Google Public DNS aims to enhance web browsing by improving DNS performance and security. It leverages Google's infrastructure to provide faster, more valid DNS results, reducing the load on ISPs' servers. Key actions include using large-scale caches, load balancing, and implementing security measures like DNSSEC, entropy additions, and rate-limiting to prevent spoofing and denial-of-service attacks. It does not provide top level domain (TLD) name service, host DNS applications, or blocks malwares. It ensures it returns the right answer to queries.\n"],null,["# Introduction to Google Public DNS\n\nWhy Google Public DNS?\n----------------------\n\nAs web pages become more complex and include more resources from multiple origin\ndomains, clients need to perform multiple DNS lookups to render a single page.\nThe average Internet user performs hundreds of DNS lookups each day,\nslowing down their browsing experience.\nAs the web continues to grow, greater load is placed on existing DNS\ninfrastructure.\n\nSince Google's search engine already crawls the web on a daily basis and in the\nprocess resolves and caches DNS information, we wanted to leverage our\ntechnology to experiment with new ways of addressing some of the existing DNS\nchallenges around performance and security.\nWe are offering the service to the public in the hope of achieving the following\naims:\n\n- Provide end users with an alternative to their current DNS service. Google Public DNS takes some new approaches that we believe offer more valid results, increased security, and, in most cases, better performance.\n- Help reduce the load on ISPs' DNS servers. By taking advantage of our global datacenter and caching infrastructure, we can directly serve large numbers of user requests without having to query other DNS resolvers.\n- Help make the web faster and more secure. We are launching this service to test some new ways to approach DNS-related challenges. We hope to share what we learn with developers of DNS resolvers and the broader web community and get their feedback.\n\nGoogle Public DNS: what it is and isn't\n---------------------------------------\n\nGoogle Public DNS is a recursive DNS resolver, similar to other publicly\navailable services.\nWe think it provides many benefits, including improved security,\nfast performance, and more valid results.\nSee below for an overview of the technical\nenhancements we've implemented.\n\nGoogle Public DNS is not, however, any of the following:\n\n- A top-level domain (TLD) name service.\n- A DNS hosting or failover service. Google Public DNS is not a third-party DNS application service provider that hosts authoritative records for other domains. If you are looking for a high-volume, programmable, authoritative name server using Google's infrastructure, try [Google's Cloud DNS](//cloud.google.com/dns/).\n- An authoritative name service. Google Public DNS servers are not authoritative for any domain. Google maintains another set of name servers that are authoritative for domains it has registered, hosted at ns\\[1-4\\].google.com.\n- A malware-blocking service. Google Public DNS rarely performs blocking or filtering, though it may if we believe this is necessary to protect our users from security threats, or as required by law. In such extraordinary cases, it fails to answer; it does not create modified results.\n\nOverview of benefits and enhancements\n-------------------------------------\n\nGoogle Public DNS implements a number of security, performance, and compliance\nimprovements.\nWe provide a brief overview of those enhancements below.\nIf you're a developer or deployer of DNS software, we hope you'll also read the\ntechnical information pages on this site for more information on these features.\nUltimately, our hope is to share our insights and inspire the community to adopt\nsome of these features in all DNS resolvers.\nThe changes are grouped into 3 categories:\n\n### Performance\n\nMany DNS service providers are not sufficiently provisioned to be able to\nsupport high-volume input/output and caching, and adequately balance load among\ntheir servers.\nGoogle Public DNS uses large, Google-scale caches, and load-balances user\ntraffic to ensure shared caching, letting us answer a large fraction of queries\nfrom cache.\n\nFor more information, see the page on [performance benefits](/speed/public-dns/docs/performance).\n\n### Security\n\nDNS is vulnerable to various kinds of spoofing attacks that can \"poison\"\na name server's cache and route its users to malicious sites.\nThe prevalence of DNS exploits means that providers have to frequently apply\nserver updates and patches.\nIn addition, open DNS resolvers are vulnerable to being used to launch\ndenial-of-service (DoS) attacks on other systems.\nTo defend against such attacks, Google has implemented several recommended\nsolutions to help guarantee the authenticity of the responses it receives from\nother name servers, and to ensure our servers are not used for launching DoS\nattacks.\nBesides full support of the DNSSEC protocol, these include adding entropy to\nrequests, rate-limiting client traffic, and more.\n\nIn addition, Google Public DNS may not resolve certain domains if we believe\nthis is necessary to protect Google's users from security threats.\n\nFor more information, see the page on [security benefits](/speed/public-dns/docs/security).\n\n### Correctness\n\nGoogle Public DNS does its best to return the right answer to every query every\ntime, in accordance with the DNS standards.\nSometimes, in the case of a query for a mistyped or non-existent domain name,\nthe right answer means no answer, or an error message stating the domain name\ncould not be resolved.\nIt also may not resolve certain domains if we believe this is necessary to\nprotect our users from security threats.\nGoogle Public DNS never redirects users, unlike some open resolvers and ISPs."]]
