Google 提供 Public DNS Resolver

Posted on December 4, 2009 by Gea-Suan Lin

在 TC 看到 Google 公開了 Public DNS Resolver 服務：「Google Gets Into The DNS Business. Here’s What That Means」。

與 OpenDNS 不同，他不會把無法 resolve 的 request 導到廣告頁，另外又因為密度比 OpenDNS 高 (因為 Google 在很多地方有機房)，IP address 又好寄 (分別是 8.8.8.8 與 8.8.4.4)，就基本的 resolver 功能來說，OpenDNS 沒有優勢。

不過我發現如果是查詢 Akamai CDN，反而會被導到美東 (，EdgeCast 則是美西。不過 Limelight Networks 與 CDNetworks (Panther Express 部份) 都還蠻正常的，都是正確送到亞洲區的 PoP。以目前大多數的網站都是用 Akamai，用 Google 提供的 Public DNS Resolver 反而會變慢而非變快。

有興趣的人可以用看看感覺一下？

Related Posts:

  • No Related Posts
This entry was posted in Computer, DNS, Murmuring, Network. Bookmark the permalink.
  • http://scrappedblog.blogspot.com/ Roy

    TTL LFT trace to google-public-dns-a.google.com (8.8.8.8):53/tcp
    2 [9269] [CTIHK] 061244085xxx.ctinets.com (61.244.85.xxx) 2.3/2.0/1.9ms
    3 [9269] [CTIHK] 061244055145.static.ctinets.com (61.244.55.145) 1.6/2.5/2.5ms
    4 [9269] [CTIHK] 061238169053.ctinets.com (61.238.169.53) 2.7/2.5/2.7ms
    5 [9269] [CTIHK] 061238225149.ctinets.com (61.238.225.149) 2.6/2.4/2.4ms
    6 [9269] [CTIHK] 061244232217.static.ctinets.com (61.244.232.217) 2.5/2.8/2.7ms
    7 [9269] [CTIHK] 061244232237.static.ctinets.com (61.244.232.237) 2.5/3.7/3.1ms
    8 [15169] [GOOGLE] 72.14.216.173 3.6/4.2/4.1ms
    9 [15169] [GOOGLE] 64.233.175.207 5.7/5.2/6.7ms
    10 [15169] [GOOGLE] 209.85.241.58 4.9/5.2/4.8ms
    11 [15169] [GOOGLE] 209.85.250.120 26.8/27.5/25.6ms
    12 [15169] [GOOGLE] 209.85.243.23 25.5/25.1/33.2ms
    13 [15169] [GOOGLE] 209.85.241.166 32.9/28.1/27.1ms
    14 [15169] [LVLT-GOOGL-1-8-8-8] [target open] google-public-dns-a.google.com (8.8.8.8):53 27.0/26.0/27.4ms
    TTL LFT trace to google-public-dns-b.google.com (8.8.4.4):53/tcp
    2 [9269] [CTIHK] 061244085xxx.ctinets.com (61.244.85.xxx) 3.1/2.0/1.9ms
    3 [9269] [CTIHK] 061244055145.static.ctinets.com (61.244.55.145) 1.6/1.6/1.7ms
    4 [9269] [CTIHK] 061238169053.ctinets.com (61.238.169.53) 2.4/2.9/2.7ms
    5 [9269] [CTIHK] 061238225149.ctinets.com (61.238.225.149) 2.4/2.5/2.4ms
    6 [9269] [CTIHK] 061244232217.static.ctinets.com (61.244.232.217) 2.6/2.7/2.7ms
    7 [9269] [CTIHK] 061244232237.static.ctinets.com (61.244.232.237) 2.7/4.3/3.4ms
    8 [15169] [GOOGLE] 72.14.196.149 5.6/4.0/4.1ms
    9 [15169] [GOOGLE] 64.233.175.207 4.3/4.7/4.4ms
    10 [15169] [GOOGLE] 209.85.241.56 5.2/4.2/4.2ms
    11 [15169] [GOOGLE] 209.85.250.122 22.6/22.7/24.6ms
    12 [15169] [GOOGLE] 209.85.250.101 24.7/25.7/25.4ms
    13 [15169] [GOOGLE] 209.85.241.154 35.4/24.9/27.1ms
    14 [15169] [LVLT-ORG-8-8] [target open] google-public-dns-b.google.com (8.8.4.4):53 25.7/25.7/25.8ms
    我這邊trace過去都是去Google/Level3…原因是這個吧。

  • http://blog.gslin.org/ Gea-Suan Lin

    不太對，主要是 Akamai/EdgeCast 資料庫的資料不夠正確吧？多實驗幾次可以發現台灣 DNS resolver 對外 query 的 IP address 是 72.14.202.94 (或是鄰近的 IP address)，而這些 IP address 資訊還沒有被更新。