Ping SMTP server before actually sending out verification emails

[Nul-led]

Pinging the SMTP server behind an email (sending a cheap ICMP) allows to easily check for invalid email providers without having to rely on sending the verification email as a proof.

Other options:

• Allowlist of email providers
• Sending the email regardless of availability of the service

[Naviary2]

Nice suggestion! Currently I have no feedback on whether or not the sent email was a success. It tells me "email sent!" but I check and the email didn't actually exist.

[Naviary2]

We decided to go with the node-email-verifier package for this. But it's still be be implemented.
https://discord.com/channels/1114425729569017918/1115358966642393190/1336421050166153304

[Naviary2]

Turns out it can only verify the domain exists, not whether the email exists. That's cool, it's still an upgrade.

This issue remains open though as we still aren't checking if emails exist. We concluded its a lot harder to do that part without paying for a service. Once the website grows enough and is profitable to merit paying for a service like that, this is something we could go with.
https://www.npmjs.com/package/email-verifier

(btw thanks @xa31er for helping add node-email-verifier in this PR #412 )