How to Check whether an Email Address is Valid?

Most Internet users consider the process of sending emails is very easy and involves only the sender sending the email and the receiver receiving it.  But in reality emails work in a more complex manner than assumed by many. Any sort of discrepancy between the interacting servers will lead to mail bounce. A major reason being, invalid email addresses of recipients.

This blog post will cover how to check whether an email address is valid or not. But before that let’s just briefly know the working principle of emails to make sure where a sent email can go wrong. At first the mail sent by the sender goes to an outgoing mail server using SMTP (Simple Mail Transfer Protocol). They sort the emails they receive and send it to the DNS (Domain Name System) server. The domain is noted and now the SMTP has the required information about the domain. It then sends the mail to the target domain’s MTA (Mail transfer Agent). It then decides where exactly to send the mail, i.e. to the receiver’s inbox.

email_finalSteps to Verify a Valid Email Id Address:

Follow the steps to check whether an email id exists or not. Let’s verify the validity of the email address

  • Enable telnet in Windows
  • In Command Prompt from your computer, type the following command:

nslookup  – type=mx

This command will extract and list the MX records of a domain. Note the MX records for listed below: MX preference=30, exchanger = MX preference=20, exchanger = MX preference=5,  exchanger = (lowest preference no.) MX preference=10, exchanger = MX preference=40, exchanger =

Replace with the domain of the email address that you wish to verify.

  • It is normal to have multiple MX records for a domain. Select any one of the servers, preferably the one with lowest preference level number.
  • Pretend to send a text message to that server from your computer. You can do this by the following way:
  1. Go to Command Prompt Window
  2. Type the following commands in the given listed sequence:
    1. Connect to the mail server: telnet 25
    2. Say ‘hello’ to the other server: HELLO
    3. Identify yourself with a fictitious email address:

    mail from:<>

Enter the recipient’s email id you wish to verify: rcpt to:techno.flix@gmail.comarticle-new_ehow_images_a05_mq_6s_check-email-addresses-800x800

The server response to the command ‘rcpt to’ will give you an idea whether the email address is a valid one or not. You will get any one of the following response:

  • OK – The recipient’s email address is a valid one
  • 550 Error – Either recipient’s email address is disabled or it doesn’t exist.
Swasti Pujari
Swasti Pujari

Swasti Pujari is a versatile Engineer, blogger, content writer, and Social Media Enthusiast. With a passion for technology and creativity, she has devoted her career to solving engineering challenges and crafting engaging content. Her online presence is a strategic platform for connecting with people and sharing insights. Swasti's unique blend of technical expertise and creative expression has made her a key figure in her field. Her mantra for success is continuous learning and happiness in her work, reflecting her innovative approach to both engineering and writing.

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