Eclipse Communications’ Decision to Discontinue Support for Port 25: A Move Towards Enhanced Cybersecurity


In a digital world where cybersecurity is paramount, Eclipse Communications has taken a significant step by discontinuing support for port 25 for email submission. This decision aligns with the industry’s best practices and reflects the stance of many large providers who have already blocked the use of port 25 traffic.

The Insecurity of Port 25

Port 25 was the original network port used for Simple Mail Transfer Protocol (SMTP), the protocol responsible for sending emails. However, its widespread use also made it an attractive target for cybercriminals.

The lack of encryption in port 25 makes it susceptible to eavesdropping, where unauthorized users can potentially read or modify emails during transmission. Additionally, spammers often exploit port 25 to send out massive amounts of unsolicited emails, leading to an increase in spam traffic.

Why Eclipse Communications Made the Decision

Eclipse Communications’ decision to stop supporting port 25 reflects a commitment to enhance their clients’ cybersecurity. By blocking port 25, Eclipse Communications can significantly reduce the possibility of email-related cyber threats affecting their clients.

Moreover, this move aligns Eclipse Communications with industry standards. Many large providers such as Verizon, AT&T, NetZero, Charter, People PC, Cox, EarthLink, Verio, Cablevision, and all Japanese ISPs have also discontinued support for port 25 traffic.

Moving Forward

While this change might require some adjustments, it ultimately aims to provide a safer and more secure email experience. Alternatives to port 25, such as ports 587 and 465, offer secure email transmission, reducing the risk of cyber threats.

In conclusion, Eclipse Communications’ decision to discontinue support for port 25 is a proactive measure to further protect their clients from potential cyber threats, demonstrating their commitment to providing a secure and reliable service.