On Mon, Nov 30, 2020 at 12:48:09AM +1000, Nikolai Lusan wrote:
however the domain part of the address shouldn't be case sensitive.
This is only kind of true. In the DNS, domain names match in a case-insensitive but case-preserving way, _only if_ you are talking about an ASCII letter (i.e. a-z using the US alphabet with no "decorations"). This is specified in STD 13 (RFCs 1034 and 1035). All other octets in a domain name label match exactly only. Note that with internationalized domain names in the mix, the issue is more complicated. In the current specifications (IDNA2008), capital letters aren't allowed at all, and it would be an error to encounter one in a domain name slot (such as the domain part of an email address). Bizarrely, this means that the domain names example.tld and EXAMPLE.TLD and even eXaMpLe.TlD are all equivalent, but éxample.tld is legal, éxample.TLD is legal, and ÉXAMPLE.TLD is an error. (I'm aware that's not how you spell example in French, I'm just using it for illustration.) I don't think that the above considered TLDs or EAI, so I don't expect it is relevant; I just mention it for completeness. Best regards, A -- Andrew Sullivan a...@anvilwalrusden.com
