At the first glance, I've been misslead by the keyword "banner" and the ANSI sequence. I do not delete but update this answer to preserve the helpful comments below.
Please regard this answer as a comment.
As roaima pointed out the
Banner defined in
sshd_config gets displayed at the beginning of the authentication, but your debug message is a result of kex-exchange that is done just before auth.
Also check Kamil Maciorowski, linked hint. — The tested string is part of the compiled code.
To find out more please activate at least
debug level 1 by changing the
- Restart your sshd by
systemctl restart sshd
- Note that at Debian any settings in
/etc/ssh/sshd_config.d/*.conf will take precedence over those in
/etc/ssh/sshd_config (the first match takes control).
Of interest are these entries and their neighbours:
Sep 17 01:03:43 lamp sshd: Connection from 192.168.0.1 port 43854 on 192.168.0.2 port 22 rdomain ""
Sep 17 01:03:43 lamp sshd: debug1: Local version string SSH-2.0-OpenSSH_8.4p1 Debian-5+deb11u1
Sep 17 01:03:43 lamp sshd: debug1: Remote protocol version 2.0, remote software version OpenSSH_9.2p1 Debian-2
Sep 17 01:03:43 lamp sshd: debug1: match: OpenSSH_9.2p1 Debian-2 pat OpenSSH* compat 0x04000000
- Please do retrieve this at the JumpHost and the Destination Host (Debian) for the same connection attempt and update your question by the log results.
- Also add the related output of localhost using
ssh Debian -vvv (more than just the error to see the context)
- It might be useful to also add the log of a ssh to the JumpHost itself, if there's a difference.
- Same optional interest to the ssh connection JumpHost > Destination Host
Awaiting the results ...
Regarding the above, the point that the match for
OpenSSH* is searched the relevance of some preceding "ANSI escape codes with typos" reduces to "some garbage that must not be there".
Your banner line contains a typo: Should be
\033(B, but not not
# Your line:
# Fixed line:
\033[B # tells "Move Cursor down"
\033[m # reset the ANSI colors
Part of the original answer, but most likely not the solution for the question (see above):
Configure the banner of OpenSSH Server
The file is configured in
Did you find such an entry and the configured file?
Disable the banner by
Banner none (and restart the
This has to be checked at both involved
sshd: the JumpHost and the destination.