I think the issue will not be fixed by changing the
Ciphers or any other configs for that matter, I followed this superuser thread for fixing this and only ishitatsuyuki’s reply makes sense. So I think changing the ssh config on the docker images will be enough to allow ssh logins.
the logs obtained via ssh -v says the same as it uses 128 bit key the client side is rejecting it (I’m no security expert here, feel free to correct me if I’m wrong).
debug1: SSH2_MSG_KEXINIT sent
debug1: SSH2_MSG_KEXINIT received
debug1: kex: algorithm: email@example.com
debug1: kex: host key algorithm: ssh-rsa
debug1: kex: server->client cipher: aes128-ctr MAC: firstname.lastname@example.org compression: none
debug1: kex: client->server cipher: aes128-ctr MAC: email@example.com compression: none
debug1: expecting SSH2_MSG_KEX_ECDH_REPLY
ssh_dispatch_run_fatal: Connection to <redacted> port <redacted>: Invalid key length
I think trying the same by creating a sample container with custom docker image changing the generated ssh key (I have no idea how), might fix this issue.