linux: upgrade openssh server and client

download and extract latest openssh source file from http://www.openssh.org/
# ./configure
# make
# make install


if you get a zlib too old error while configuring
download and extract latest zlib from http://www.gzip.org/zlib
# ./configure
# make
# make install

then try installing latest openssh again

you'll have to restart your server to reflect updated openssh server

to test client # ssh -v
to test server # telnet 127.0.0.1 22