This class can be used to validate an e-mail address by checking its domain.
It can check a given e-mail address by verifying if it matches a regular expression with a pattern of valid e-mail addresses.
The class can also check the existence e-mail address domain by opening a connection to a host with the e-mail domain name.

How to Work?

• check length of email address max is 320 characters where:
64 characters max for the user of email address 1 character max for the @ 255 characters max for the host name
• apply regular expressions to valid email addres string
• check if exist host to send messages to email address