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FYI, in modern ssh

  Compression delayed
is equal to

  Compression yes
which is the default already.

With regards to

  PerSourceMaxStartups
  PerSourceNetBlockSize
how do you configure it, in order to not make it a DOS vector?



> how do you configure it, in order to not make it a DOS vector?

You use it in conjunction with a third parameter that I forgot to mention, namely MaxStartups.

MaxStartups introduces a degree of randomness to the whole process, so you have MaxStartups X:Y:Z where:

     - X = Reference number of unauthenticated connections ("n")
     - Y = Percentage probability of dropping when n>X
     - Z = n=Z == all further unauthenticated connections dropped
Additional parameter that may be of interest is LoginGraceTime.

Fun fact, MaxStartups/PerSourceMaxStartups/PerSourceNetBlockSize were specifically introduced >6.1 in order to add firepower to combatting unauthenticated connection DoS attacks.




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