Generally, you need to open port 22 for a Linux instance, or port 3389 for a Windows instance. For more information about ports applicable to other instance types, see Security Group Use Cases.
For more information, see Server Common Port.
You can use the service only after you open the port to the Internet in the security group. For example:
If you want to access web pages using port 8080, the port must be enabled and opened to the Internet in the security group.
To open a port to the Internet, follow the steps below:
For more information, see Modifying the Default Remote Port of CVM.
After modifying the service port, you also need to open the corresponding port to the Internet in the security group.
|TCP||42, 135, 137, 138, 139, 445, 593, 1025, 1434, 1068, 3127, 3128, 3129, 3130, 4444, 5554, 5800, 5900, 9996|
|UDP||1026, 1027, 1434, 1068, 5554, 9996, 1028, 1433, 135 - 139|
TCP port 25 is the default email service port. For security reasons, port 25 of CVM instances is blocked by default. If you need to use it, see Unblocking Port 25.