4 ms·

My favorite is e-mails with three dots in them. Which is actually not a valid address - the RFC specifies that you must have a valid textual character between d

My favorite is e-mails with three dots in them. Which is actually not a valid address - the RFC specifies that you must have a valid textual character between dots[1]. However, because of poor decisions by Japanese telcoms, a substantial chunk of their users have 'e-mails' associated with their mobile phones with three dots, breaking goddamn every sensible validation script. [1] https://tools.ietf.org/html/rfc2822#section-3.2.4 https://tools.ietf.org/html/rfc2822#section-3.2.4

ori_b 11y ago
There's only one sensible validation script: "Send an email with a confirm link".
- GauntletWizard 11y ago
  Sadly, if you're sending e-mail sanely, your mail provider likely validates recipients, and will be annoyed at you if you send them recipients they think are bogus.
  - belovedeagle 11y ago
    The relevant rfc (on mobile; don't remember which) specifically states that intermediate servers must not validate mailboxes (local parts). And honestly the domain should be "validated" by the server doing an mx lookup; let dns handle it.
- sk5t 11y ago
  Taking action with side-effects on entirely unvalidated user input is usually a pretty bad idea.
driverdan 11y ago
> Which is actually not a valid address That means validation was working correctly. The email addresses are invalid even if the server will accept email for them.
paulmd 11y ago
So wait, what now? So you can have an email address like first.last@isp..co.jp? Can you give me a generic example? Yeah, I'm with the other guy, regardless of whether or not it's a good idea to do validation (it's not), that's not an address that should pass validation because it's not a valid domain or hostname. I could see it being less of a big deal in the mailbox portion given that it's now kinda kosher to ignore dots there.
Steko 11y ago
Yep, for some reason my wife's emails to her sister[1] always bounce unless she uses the desktop, it's madness. [1] docomo customer with two dots in email

ori_b 11y ago

There's only one sensible validation script: "Send an email with a confirm link".

GauntletWizard 11y ago
Sadly, if you're sending e-mail sanely, your mail provider likely validates recipients, and will be annoyed at you if you send them recipients they think are bogus.
- belovedeagle 11y ago
  The relevant rfc (on mobile; don't remember which) specifically states that intermediate servers must not validate mailboxes (local parts). And honestly the domain should be "validated" by the server doing an mx lookup; let dns handle it.
sk5t 11y ago
Taking action with side-effects on entirely unvalidated user input is usually a pretty bad idea.

driverdan 11y ago

> Which is actually not a valid address That means validation was working correctly. The email addresses are invalid even if the server will accept email for them.

paulmd 11y ago

So wait, what now? So you can have an email address like first.last@isp..co.jp? Can you give me a generic example? Yeah, I'm with the other guy, regardless of whether or not it's a good idea to do validation (it's not), that's not an address that should pass validation because it's not a valid domain or hostname. I could see it being less of a big deal in the mailbox portion given that it's now kinda kosher to ignore dots there.

Steko 11y ago

Yep, for some reason my wife's emails to her sister[1] always bounce unless she uses the desktop, it's madness. [1] docomo customer with two dots in email