Hello mina(sshd) devs,

While using mina-sshd I ran into a possible issue.
Basically, when connecting as a client to SSH server, session initialization 
halts. The message exchange (observed by wireshark) looked like this:

Mina-SSHD-client -> SSH server                SSH-2.0-...
Mina-SSHD-client -> SSH server                KEX_INIT
SSH server -> Mina-SSHD-client                 SSH-2.0-Cisco-1.25

No further messages were exchanged.
This does not always happen, if the timing is right and the message order looks 
like:

SSH-2.0...
SSH-2.0-Cisco-1.25
KEX_INIT
KEX_INIT

... the communication continues as expected.

So my questions would be:
Is that an issue ? Should the "SSH protocol identifiers" be exchanged first and 
only then KEX_INIT messages ? Is that message order valid by the SSH protocol 
standards ?
If so, can that be considered a possible issue in mina-sshd library and should 
it wait to send KEX_INIT only after SSH protocol identifier was received ?
Or is this just a bug in this particular SSH server...

I tested this with mina-sshd 1.16.0 and also 0.14 versions.
The SSH server is part of Cisco IOSv software (version 15.5(3) and above).

Regards,
Maroš Maršalek
Software Engineer

Frinx s.r.o.
Mlynské Nivy 48 / 821 09 Bratislava / Slovakia
+421 2 209 101 41 / 
[email protected]<mailto:2%20209%20101%2041%20/%[email protected]> / 
www.frinx.io<http://www.frinx.io>

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