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Unblocking Port 25

Last updated: 2024-01-08 09:41:35

Operation Scenarios
In the case of a unique scenario, you must use TCP port 25 for outbound connections on the CVM. This document guides you how to request unblock of port 25.
Notes
It only supports unblocking of prepaid annual or monthly CVMs and currently does not support CVMs operating on a pay-as-you-go basis.
You can only unblock port 25 for five instances for each Tencent Cloud account.
Make sure that you only use port 25 to connect to a third-party SMTP server for sending email. If you use your CVMs to send email directly, we reserve the right to permanently ban you from opening port 25.
It is recommended to prioritize the use of other ports for sending emails. For configuration guidance, see Sending Emails via Port 465.
Directions
1. Log in to the Tencent Cloud console.
2. Click your account name in the upper-right corner. Select Security Management.
3. In the left sidebar, click Unblock port 25 to go to the Unblock port 25 page.
4. Click Apply for unblocking port 25 to bring up the Apply for unblocking port 25 window.
5. In the Application for Unblocking TCP Port 25 pop-up window, you can select the region and the CVM instance for which port 25 needs to be unblocked, input details of the intended use, and set Reverse DNS (rDNS) records. Then, select I have read and accepted "Port 25 Protocol". For details, see the following figure.
Note:
Make sure you have not used up your unblocking quota. You can check the remaining quota in the lower left of the Application for Unblocking TCP Port 25 window.
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6. Click OK to complete the application. Please patiently await the platform administrator to process. You can check the approval results and causes via Moderation Status on the page.