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EmailVerify / email-verify

Node.js email SMTP verification, powered by EmailChecker.com API
https://emailchecker.com/real-time-api
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yahoo false negative #18

Closed Peege151 closed 8 years ago

Peege151 commented 8 years ago

I tried to verify my yahoo account. It comes back as success: false. It is my yahoo address so I know it's valid and gets email daily.

Thoughts?

bighappyworld commented 8 years ago

This module only does the SMTP protocol. You are still at the mercy of all of the other services out there and connecting to their email server. If you really want to know, you should telnet to the yahoo SMTP server and manually do the SMTP handshake.

I recently did this to another email server and turns out that the IP address that I connected to was part of an IP address block that some spam filter "blocks" because they are not server IPs but reserved for residential use by my ISP. Since I was connecting from one of those, it knew I wasn't a real mail server and so the spam filter rejected it.

There are a ton of different cases that can cause this, but that's an example I recently encountered.

tofutim commented 8 years ago

Wow that is pretty smart.

tofutim commented 8 years ago

kickbox claims to be able to do much of the smtp handshake work but it is pricy.

bighappyworld commented 8 years ago

If you did your verification FROM the same server as your email server and you have an MX record pointing to it along with all the proper DKIM, DMARC, reverse pointer record, & other stuff working for you, you won't fail as many spam filters. But you'd also have to check for your server IP on blacklists etc. Email is a nasty beast because of all the spammers and so they make it really painful to really do proper validation. This is why a service that does it can possibly make money.