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MODE Z / zlib

On-the-Fly Compression

Faster data transfers

Mode Z compression compresses files-on-the-fly as they are being transferred from the local computer to the remote computer and remote to local, saving bandwidth and improving transfer time.

Webmasters and server administrators will see an increase in productivity. Transfers of html, scripts or large logfiles (which are text) no longer need to be zipped before being sent via ftp and should generally experience a 3-4 times gain in data transfer time.

For example, a 60MB log file can turn into a 5MB data exchange when transferred with MODE Z enabled.

Depending on the file content, you will see different results.

Typical gains :
- Text files : ~15-20% of original size
- HTML files : ~25-30% of original size
- Media, Video, Sound : ~90-95% of original size

Note : Already compressed documents with Zip, Rar, Ace etc. will not see a noticeable gain.

How To

  1. Select Favorites > Edit Favorites from the SmartFTP menu. The Favorites window appears.
  2. From the SmartFTP Favorites window select the Favorite to be used. Right click on the Favorite and select Properties. The Properties dialog appears.
  3. Under Transfer select Compression. You can configure Mode Z settings here.

Server Support
ShareIt, Gene6 FTP Server, RaidenFTPd, Servu 5.x, FileZilla Server


  1. Draft: Deflate transmission mode for FTP
  2. zlib

zlib, mode z, compression, slow, transfer

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