ssh connection stop at "debug1: SSH2_MSG_KEXINIT sent" - problem with linux 2.6 and vista

Hi all,
I've just read something about hang after "debug1: SSH2_MSG_KEXINIT
sent" message but is not so clear what is needed to do, specially if
the server is not handled by you(me)...

Let me try to explain my situation:

Clients:
Linux with OpenSSH_4.5p1, OpenSSL 0.9.8b 04 May 2006
Windows with any sw client
Server (claim to be):
freeBSD with Remote protocol version 2.0, remote software version
OpenSSH_2.9.9p2

both kind of clients stop with the following trace:
OpenSSH_4.5p1, OpenSSL 0.9.8b 04 May 2006
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: Applying options for *
debug2: ssh_connect: needpriv 0
debug1: Connecting to omitted [omitted] port 22.
debug1: Connection established.
debug1: permanently_set_uid: 0/0
debug1: identity file /root/.ssh/identity type -1
debug1: identity file /root/.ssh/id_rsa type -1
debug1: identity file /root/.ssh/id_dsa type -1
debug1: Remote protocol version 2.0, remote software version OpenSSH_2.9.9p2
debug1: match: OpenSSH_2.9.9p2 pat OpenSSH_2.*,OpenSSH_3.0*,OpenSSH_3.1*
debug1: Enabling compatibility mode for protocol 2.0
debug1: Local version string SSH-2.0-OpenSSH_4.5
debug2: fd 3 setting O_NONBLOCK
debug1: SSH2_MSG_KEXINIT sent


But if, with any clients from both OS, we use a socks that is a linux
kernel 2.4 everything goes on its way (go ok)

So, my question is:
is there really nothing to manage in the kernel parameter (for linux)
or in the registry (for windows) to try to backward tcp packet to
kernel 2.4 ?

Hope I was clear enough ... :D

Thank in advance.

MV