Help Center/ Virtual Private Cloud/ FAQs/ Security/ Why Is Outbound Access on TCP Port 25 Blocked?

Updated on 2024-10-15 GMT+08:00

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Why Is Outbound Access on TCP Port 25 Blocked?

You cannot access an external address on TCP port 25. For example, running the Telnet smtp.***.com 25 command fails.

For security reasons, TCP port 25 is disabled in the outbound direction by default.

You do not need to enable TCP port 25, unless you want to deploy an email service on the cloud.

Outbound traffic over TCP port 25 is only blocked in CN North-Beijing1.

Use port 465 supported by the third-party email service provider.

Parent topic: Security

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