Is it possible to modify the string that the OpenSSH server displays when a raw connection is established?

It is not about the text banner displayed after the connection is established and which can be configured by the Banner parameter in sshd_config, but about the raw output the SSH server sends on a connection attempt before the handshake.

For example, given a raw telnet connection

$ telnet localhost 22
Connected to localhost.
Escape character is '^]'.

is there a way to reduce identifying information to the bare minimum?

My understanding is that SSH-2.0- must be present because it is required by the SSH protocol, but the string that follows - OpenSSH_7.2p2 - is probably not required by the protocol but I can't see a way to change or remove it without recompiling.

The intent is to avoid providing more info than strictly necessary for the protocol to work.


2 Answers 2


No. The version string is defined in version.h of OpenSSH source as

#define SSH_VERSION "OpenSSH_7.4".

You could change it, but it requires recompiling.

It is then send put together via:

snprintf(buf, sizeof buf, "SSH-2.0-%.100s\r\n", SSH_VERSION)

(ssh_api.c line 381, in function _ssh_send_banner)

See also: Prevent SSH from advertising its version number.


Recent OpenSSH versions allow adding custom text via VersionAddendum, but do not allow removing the product name/version. You'll have to patch the source code for that.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge that you have read and understand our privacy policy and code of conduct.

Not the answer you're looking for? Browse other questions tagged or ask your own question.