Adding a Subdomain for a Different Product Wiped Other A Records (Onamae.com / 01.dnsv.jp Sends the Entire Zone)
機械翻訳 / Machine-translated
1日前・3分で読める
機械翻訳 / Machine-translated
Because the DNS record settings screen on Onamae.com sends the entire zone at once rather than just the one record you edited, simply adding a single subdomain for a different product can silently delete existing A records that weren't included in the snapshot at that moment. HTTP monitoring kept returning 200 for several minutes, protected by the resolver's cache, so the deletion went unnoticed.
The DNS record settings screen on Onamae.com sends the entire zone it has loaded at that point, not just the one record you edited. When multiple small web services operated by the same company share the same zone under the same registrar, work done for one service silently deleted the A record for the other service's subdomain. To make matters worse, HTTP monitoring kept returning 200 for several minutes thanks to the DNS resolver's cache, so the problem wasn't caught on the spot.
Detailed step-by-step explanations, how to verify the behavior, and frequently asked questions are compiled in the original article.