2020.example.com is a valid fqdn

[Spone]

Currently in strict mode:

EmailValidator.valid?("[email protected]", mode: :strict)
=> false

but 2020.example.com is indeed a valid FQDN, right?

[karlwilbur]

Thanks, @Spone, good catch. I was operating on the RFC-952 spec which disallows hostnames beginning with non-alpha characters. This was definitely changed in the last 35 years (for example, RFC-1123), and I should have caught that. I do know that hostnames can consist of only numbers, but primary domains cannot be only numeric.

This example should be valid in all modes. I'll use your example above in the spec and get it fixed. I'll expect to have that done later today.

[karlwilbur]

Fixed in v2.2.1.

Thanks, @Spone, for reporting!

[Spone]

Thanks a lot, I managed to catch the issue by running the validation on a production database export, so thank you anonymous user who has a uncommon email :)

[delphaber]

I think primary domains can be only numeric. For example, the strict mode is marking emails like [email protected] as invalid, but it turns out that 163.com is a chinese service provider and so theirs email are valid 🤔 . I've created a PR to add a failing test: #70

[xiaohui-zhangxh]

I think primary domains can be only numeric. For example, the strict mode is marking emails like [email protected] as invalid, but it turns out that 163.com is a chinese service provider and so theirs email are valid 🤔 . I've created a PR to add a failing test: #70

This is true, 163.com, 139.com are most famous service provider in China, there are many emails are marked as invalid due to this issue.

[karlwilbur]

Yes! Thanks for catching this. @delphaber, can you please add this as a separate issue? Specifically something like "valid numeric domains are considered invalid strict mode."

I see the failing test in your PR. Thanks! Yeah, that will help make sure that we don't break it again, but I need to get in there and fix the validation RegEx. I hope to get to that in the next couple days.

[karlwilbur]

Specifically, for my own reference, RFC 1123 states:

2.1 Host Names and Numbers

The syntax of a legal Internet host name was specified in RFC-952
[DNS:4]. One aspect of host name syntax is hereby changed: the
restriction on the first character is relaxed to allow either a
letter or a digit. Host software MUST support this more liberal
syntax.

[delphaber]

can you please add this as a separate issue? Specifically something like "valid numeric domains are considered invalid strict mode."

will do!