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Tune up SSH packet parameters

All SSH data exchange on its lowest layer is performed in packets. Each packet can be viewed as an envelope for some piece of protocol data. Each SSH packet is individually encrypted, sent over and processed by the receiving party. So a packet can be viewed as an exchange primitive.

SSHBlackbox allows to fine-tune the parameters of the packets it sends to achieve better compatibility with certain constrained or buggy servers. While you will rarely need to adjust packet properties in real world, it is good to know you can do that and how you can do that.

  • DefaultWindowsSize (default: 2048000 bytes): the size of the 'receive window', i.e. how many incoming bytes the component can 'cache' internally before giving them back to the user. This affects the amounts of data the remote side sends 'in one ago' (before receiving a confirmation that the client side can receive more data). Decreasing DefaultWindowSize may help to decrease resource burden on the client (e.g. in constrained environments), and increasing it may improve the transfer speed.
  • MinWindowSize (default: 2048 bytes): the minimal size after reaching which the 'window extension' request is sent to the server to notify it that the window was extended and it can send more data.
  • MaxSSHPacketSize (261120 bytes): the maximal size of SSH packet. Decreasing it may help resolve compatibility issues in some cases.
  • ForceCompression/CompressionLevel: switch on and off compression settings.

How To articles about SFTP client

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