What is EHLO?
EHLO (Extended HELO) is a command sent by an email client to an email server to identify itself when initiating an
SMTP (Simple Mail Transfer Protocol) session. It allows the client to inform the server of its capabilities and request the server's capabilities in return.
Authentication: Ensures that emails are sent from a legitimate source, reducing the risk of
spam and
phishing.
Deliverability: Helps in improving
email deliverability by establishing a secure communication channel between the client and the server.
Feature Negotiation: Allows the client and server to negotiate features like
TLS encryption, enhancing the security of email transmissions.
How Does EHLO Work?
When an email client initiates a connection to an SMTP server, it typically starts with the EHLO command. The server responds with a list of supported
SMTP extensions. This exchange ensures both parties are aware of each other's capabilities, allowing for a more secure and efficient communication process.
Enhanced Security: By using EHLO, email clients and servers can support advanced security features like
STARTTLS.
Better Deliverability: Emails are less likely to be marked as spam when EHLO is used correctly, as it helps in proper authentication.
Improved Reporting: EHLO allows for the use of advanced reporting tools, providing valuable insights into email campaigns.
Misconfiguration: Incorrect setup can lead to failed email deliveries.
Compatibility: Some older servers may not fully support EHLO, leading to potential communication issues.
Security Risks: If not properly secured, EHLO can be exploited by malicious actors to send spam or phishing emails.
Check Server Logs: Review the server logs to identify any EHLO-related errors.
Verify Configuration: Ensure that your SMTP server and email client are correctly configured to use EHLO.
Update Software: Make sure both your email client and server software are up-to-date to support the latest EHLO features.
Conclusion
EHLO is a fundamental component of modern
email marketing strategies. By understanding its importance and addressing common issues, marketers can enhance the security, deliverability, and effectiveness of their email campaigns. Ensure that your
SMTP servers and email clients are properly configured to take full advantage of EHLO and its benefits.