Currently using:
Verification level
Performs a syntactical validation of the provided email address against RFC 2821
and RFC 2822 rules.
Queries the DNS server for an MX record for the email address domain, checking if
one exists and is available to use.
Verifies that the provided address is not a
disposable email address (DEA).
Checks if a connection could be performed to the mail server of the email address
domain.
Checks whether the mail server accepts or rejects messages sent to the required
email address.
Checks if the mail server accepts messages sent to the required email address while
rejecting messages sent to non existent email addresses.