Email Checker is a simple online tool for verifying an email address. It's free and quite easy to use. Just enter the email address and hit Validate button. Then it tells you whether the email address is real or fake.
It extracts the MX records from the email address and connect to mail server (over SMTP and also simulates sending a message) to make sure the mailbox really exist for that user/address. Some mail servers do not co-operate in the process, in such cases, the result of this email verification tool may not be as accurate as expected
Step-2:- As you noticed that output of the nslookup, MX records may be multiple choose any but prefer to choose lowest level no. After that run this command:
telnet gmail-smtp-in.l.google.com 5
Step-3:- Say hello to server.
helo
Step-4:- Set sender email id.
mail from: <[email protected]>
Step-5:- Set the recipient’s email address to whom you are trying to verify:
rcpt to: <[email protected]>
The responseof the server for ‘rcpt to’ command will give you an idea whether an email address is valid or not. You’ll receive an “OK” if the address exists else a 550 error like:
[email protected] – OK (Email id is valid).
[email protected] – The email account that you tried to reach does not exist(Email id may be fake).
See Below attached screen shot