protocol SFTP and TLS 1.2 hand shake, sending files

Question

Question If client A is using TLS 1.2 protocol and client B is using SFTP protocol (SSH), Can client A or B, be able send files between them without having security conflict, Or do they need to be on the same protocol?

Answer 1

(SFTP is a layer on top of the SSH protocol)

The SSH protocol and TLS have nothing to do with each other. Each is a layer sitting on top of TCP. Both provide the same function: to create a secure channel/tunnel for the communication of arbitrary byte streams.

If a client is "speaking" TLS, then it must be talking to a server "speaking" the server-side of the TLS protocol.

Likewise, if a client is "speaking" SSH, it can only be talking to a server speaking "SSH". This is the meaning of "protocol" -- a well defined set of rules for communications. A client speaking one protocol cannot communicate with a server speaking a different protocol. An FTP client cannot speak FTP with an IMAP server speaking the IMAP protocol. It would make no sense, just like it makes no sense for a TLS client to be speaking with an SSH server.

It is possible, however, to tunnel TLS through SSH. See: https://www.example-code.com/csharp/socket_tlsSshTunnel.asp

or you can tunnel other protocols through SSH.
See: https://www.example-code.com/csharp/sshTunnel.asp

you can also do other things, like run SSH through HTTP: https://www.example-code.com/csharp/sftp_http_proxy.asp