Ssh can’t set compression level to more, than 6

compressionssh

When I do (I've tried various ways):

ssh -v -C -o CompressionLevel=9 user@ip
ssh -v -C -o 'CompressionLevel=9' user@ip
ssh -v -o 'Compression=yes' -o 'CompressionLevel=9' user@ip
ssh -v -o 'CompressionLevel=9' -o 'Compression=yes' user@ip
ssh -v -C -o 'CompressionLevel 9' user@ip
ssh -v -o 'Compression yes' -o 'CompressionLevel 9' user@ip
ssh -v -o 'CompressionLevel 9' -o 'Compression yes' user@ip

I enabled -v, so I can see connection details and no matter, what I tried, I can't get compression level more than 6, as it shows in verbose output:

debug1: Enabling compression at level 6.

I don't need to set CompressionLevel in ssh_config, I need to do it with cli.

I've found some info, that the option CompressionLevel works only for ssh version 1, but not 2.

How to set the maximum compression level for ssh version 2 protocol?

Best Answer

You can't. As the man page clearly states, CompressionLevel is an option only for protocol version 1.

See this for a possible alternative, but unless you are on a real slow or expensive connection, just using the default is a much better approach.

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