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Direct Mail:SMTP service endpoints

Last Updated:May 26, 2026

SMTP service endpoints for each region.

Region

Endpoint

China (Hangzhou)

smtpdm.aliyun.com

Singapore

smtpdm-ap-southeast-1.aliyuncs.com

US (Virginia)

smtpdm-us-east-1.aliyuncs.com

Germany (Frankfurt)

smtpdm-eu-central-1.aliyuncs.com

SMTP port numbers: 25, 80, and 465 (for SSL encryption).

Note
  • Port 25 is disabled by default on Alibaba Cloud ECS and Web Hosting instances. Use port 80 (non-SSL) or port 465 (SSL) instead.

  • You can also use STARTTLS to enable explicit SSL/TLS on port 25 or 80.

Select the endpoint that matches your console region.

To send from other regions such as China (Hong Kong), How to select a sending region.

Note

Legacy endpoints (not recommended for new users):

  • Singapore: smtpdm-ap-southeast-1.aliyun.com

  • Australia (Sydney): smtpdm-ap-southeast-2.aliyun.com

If you encounter connectivity issues, run these commands and capture the output:

1. Get the IP address: ping smtpdm.aliyun.com

2. Test port connectivity: telnet smtpdm.aliyun.com 80

3. Check for route packet loss: mtr -n -i 1 -c 100 smtpdm.aliyun.com

4. Capture packets (use a non-encrypted port such as 80 or 25 while reproducing the issue): tcpdump -i any -n host smtpdm.aliyun.com and port 80 -w package.pcap

Note

Replace the endpoint and port with your actual values.