I agree. The article even says that these odd formats are used to bypass filters but cannot pinpoint why BSD 4.2 added support for them in 1983. It hints that

I agree. The article even says that these odd formats are used to bypass filters but cannot pinpoint why BSD 4.2 added support for them in 1983. It hints that certificate validation fails in some cases, but that seems even more niche. What applications are using certs with IP-in-CN anyway in 2021? Shouldn't any IPs be in the "typed" SAN extension? Commit is here: https://github.com/curl/curl/commit/56a037cc0ad1b2a770d0c08d3d09dee1ce600f0f https://github.com/curl/curl/commit/56a037cc0ad1b2a770d0c08d...