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Alibaba Mail:Explanation of Attachment Detection Rules in Email Monitoring

Last Updated:Jun 17, 2026

Attachment detection in email monitoring follows specific rules for supported file types, size limits, and extraction depth.

1. Only standard attachments are scanned for content detection.

2. Large attachments and shared links from DingTalk documents are not parsed or detected.

3. Compressed files up to 50 MB are supported. Accepted formats: .zip, .rar, .tar, .tar.gz, .tar.xz, .7z, and .tar.bz2.

4. The maximum extraction depth is five layers, and up to 100 files can be extracted from a single archive.

5. Supported document formats include PDF files under 5 MB (image-based PDFs are excluded), DOC, DOCX, PPT, PPTX, XLS, and XLSX.

6. Other file types under 50 MB are supported, with keyword matching applied to the first 1 MB of text.