Type a number to configure a restriction for the number of decompressed files that IM Security will scan. When the amount of decompressed files within the compressed file exceeds this number, then IM Security only scans files up to the limit set by this option.

Type a number that represents the size limit in MB. IM Security only scans compressed files that are smaller or equal to this size after decompression.

Type a number from 1-20. IM Security only scans compressed files that have less than or equal to the specified layers of compression. For example, if you set the limit to 5 layers of compression, then IM Security will scan the first 5 layers of compressed files, but not scan files compressed to 6 or more layers.

IM Security only scans compressed files when the ratio of the size of the decompressed file compared to the size of the compressed file is less than or equal to this number.

This function prevents IM Security from scanning a compressed file that might cause a Denial-of-Service (DoS) attack. A Denial-of-Service (DoS) attack happens when a mail server’s resources are overwhelmed by unnecessary tasks. Preventing IM Security from scanning files that decompress into very large files helps prevent this problem from happening.