127.0.53.53 is a special IPv4 address that will appear in system logs alerting system administrators that there is potential name collision issue, enabling a quick diagnosis and remediation. The "53" is used as a mnemonic to indicate a DNS-related problem owing to the use of network port 53 for the DNS service.
[2] ICANN理事会による名前衝突問題への対応フレームワーク承認のアナウンス - JPNIC (Japan Network Information Center 著, 版) <https://www.nic.ad.jp/ja/dom/new-gtld/name-collision/framework-announcement.html>
[3] ChromeのERR_ICANN_NAME_COLLISION - あすのかぜ ( 版) <http://d.hatena.ne.jp/ASnoKaze/20150329/1427615867>
[4] Issue 1035803003: Fail DNS resolution if the result contains 127.0.53.53. - Code Review ( 版) <https://codereview.chromium.org/1035803003/>
[5] Issue 1002283005: Add an error page for net::ERR_ICANN_NAME_COLLISION. - Code Review ( 版) <https://codereview.chromium.org/1002283005/>
[6] ICANN Approves Name Collision Occurrence Management Framework | Special IP Address (127.0.53.53) Alerts System Administrators of Potential Issue - ICANN ( 著, 版) <https://www.icann.org/news/announcement-2-2014-08-01-en>
[7] ICANN Approves Name Collision Occurrence Management Framework | Special IP Address (127.0.53.53) Alerts System Administrators of Potential Issue - ICANN ( 著, 版) <https://www.icann.org/news/announcement-2-2014-08-01-en>