How to Use Email Lookup for Accurate Email Address Verification?

It's easy and free with our tool. Email lookup, also called a checker or verifier, is a fast and accurate free online IP tool. It checks email existence through multi-stage verification and also examines the SMTP server's IP, identifying its location. For deeper analysis, use our Email Tracker to trace the sender's IP address through email headers and advanced verification.

Email Validation Process via SMTP

The check-in process is completed through the following steps:

  • Connection to the SMTP server of the requested email address is established via port 25. It is the standard Simple Mail Transfer Protocol (SMTP) port for sending and receiving emails. For example, the SMTP server for the email address [email protected] is hotmail-com.olc.protection.outlook.com, which resolves to the SMTP server IP address 52.101.9.1 located in Washington (USA).
  • If the connection is successful, our email tool will verify the email. It does so by sending an SMTP HELLO command to the server, requesting it to verify the email address.
  • Once the SMTP server accepts our request and processes our query, it informs us whether the E-Mail ID/Recipient is valid or not.
  • The final step of validation is to show the SMTP server's result. It will confirm whether the email address is valid, with three possible outcomes:
    - SMTP server states that the email address is valid.
    - SMTP server states that the email address is not valid.
    - It was not possible to determine if it is valid deliverable e-mail box address.
  • Once we get answer we disconnect from SMTP server.
  • Then, based on the IP obtained from the SMTP server of the verified email, you can easily track its location using our IP lookup tool.
 

How to Check and Validate an Email Address for Free?

Enter the email address you want to lookup below. Our trustworthy tool will check email and give you detailed information about the process of checking your email address.

 
 

Common Email Status Codes Explained

When an email is sent, the server replies with a status code. These codes tell you if the email was delivered, delayed, or rejected.

πŸ“˜ Code Groups

  • βœ… 2xx – Successful delivery
    Example: 250 OK – The message was accepted and delivered.
  • ⏳ 4xx – Temporary error
    Example: 421 Service not available – The server is busy or unavailable. Try again later.
  • ❌ 5xx – Permanent error
    Examples:
    • 550 – The recipient does not exist.
    • 554 – The message was rejected, often marked as spam.

πŸ“© Most Common Codes

  • βœ… 250 OK - The email was delivered successfully.
  • ⏳ 421 Service not available - The mail server is temporarily down or overloaded.
  • πŸ“₯ 450 Mailbox unavailable - The recipient's inbox is busy or cannot be accessed.
  • πŸ› οΈ 451 Temporary local problem - The server had an issue; try again later.
  • πŸ’Ύ 452 Insufficient system storage - The server cannot store the message.
  • 🐞 500 Syntax error - Invalid command was sent to the mail server.
  • 🚫 550 Requested action not taken - The recipient address does not exist.
  • πŸ“€ 551 User not local - The server cannot forward the email.
  • πŸ“¦ 552 Exceeded storage limit - The recipient's mailbox is full.
  • βœ‰οΈ 553 Invalid address - The email address format is incorrect.
  • πŸ”’ 554 Transaction failed - The message was rejected (possible spam or policy block).