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ssh(1)
small SSH client
Package: dropbear, added for amigaux.
Also by this name: dbclient(1), General commands
NAME
dbclient, ssh - small SSH client
SYNOPSIS
dbclient [ -tTNfgyz ] [ -p port ] [
-i keyfile ] ... [ -L forward ] [ -R
forward ] [ -l user ]
[user@]host[^port] [ command ]
dbclient [ options ]
[user@]host1,[user@]host2,...
DESCRIPTION
dbclient logs in to host over SSH, version 2, and runs command there, or a login shell when no command is given. It is also installed as ssh, the name other programs call (rsync's -e, for one); its options are its own, not OpenSSH's. It is the client of the Dropbear SSH programs; see dropbear(8). It offers the same algorithms as the server (see ALGORITHMS in dropbear(8)), so it talks to any SSH server of the last ten years. Of a server's host keys it asks for the RSA one (rsa-sha2-256) first, which is ten times cheaper to verify on this machine than ed25519, and then the ed25519 one.
It authenticates with a key first, then with a password. The keys it tries are ~/.ssh/id_dropbear and those given with -i; make one with dropbearkey(1).
At the first connection to a host it shows the host key's fingerprint and asks whether to trust it; the key is then kept in ~/.ssh/known_hosts, and a later connection whose host key differs is refused.
OPTIONS
- command
- Run command on the remote host with the user's shell. The command starts at the first argument after host that is not an option.
- -p port
- Connect to port (default 22); also written host^port.
- -i keyfile
- Use the key in keyfile, a key in Dropbear's format as dropbearkey(1) makes it. May be given more than once.
- -L [address:]lport:host:port
- Forward the local port lport through the connection to host:port.
- -R [address:]rport:host:port
- Forward the remote port rport through the connection to host:port here.
- -l user
- Log in as user; also written user@host.
- -t
- Allocate a terminal (the default without a command).
- -T
- No terminal (the default with a command).
- -N
- Run no command; for port forwarding.
- -f
- Go into the background after logging in (needs a command or -N).
- -g
- Let other hosts connect to forwarded ports.
- -y
- Accept an unknown host key without asking (a changed one is still refused); given twice, check no host key at all, which is unsafe.
- -W window
- The receive window of each channel, in bytes (default 24576).
- -K seconds
- Send a keepalive after seconds without traffic (0, the default, sends none).
- -I seconds
- Close the connection after seconds without traffic (0, the default, never).
- -z
- Do not mark the traffic with the AF21 class of service.
- -J command
- Talk to the server through the standard input and output of command, run by the shell, instead of a TCP connection; host still names the host key.
- -B host:port
- Connect to host:port through the server and join it to the standard input and output, as netcat does.
- -c ciphers
- -m macs
- Offer only these ciphers or MACs, separated by commas; help lists them.
- -o option=value
- An option in OpenSSH's form: BatchMode, BindAddress, ExitOnForwardFailure, GatewayPorts, IdentityFile, PasswordAuthentication, Port, ProxyCommand, ServerAliveInterval, StrictHostKeyChecking (yes, no or accept-new) and UseSyslog.
- -s
- Request command as a subsystem.
- -b [address][:port]
- Connect from this local address or port.
- -Q what
- List the algorithms of one kind: kex, sig, cipher, mac or compress.
- -V
- Print the version.
MORE THAN ONE HOP
Hosts separated by commas are reached one through the other: the client logs in to the first, then through a forwarded connection to the next, and so on. Each hop is authenticated end to end; a host on the way sees only encrypted traffic.
ESCAPES
With a terminal, a newline followed by ~. ends the connection, ~^Z puts it in the background and ~R makes new session keys.
ENVIRONMENT
- DROPBEAR_PASSWORD
- The password to log in with. Other users can read a process's environment with ps(1), so use a key instead where you can.
FILES
- ~/.ssh/id_dropbear
- The default key.
- ~/.ssh/known_hosts
- The host keys trusted so far, in OpenSSH's form.
SEE ALSO
NOTES
A key made by OpenSSH's ssh-keygen cannot be read here; make a key with dropbearkey(1) and add its public half, which dropbearkey -y prints, to the server's authorized_keys.
| 1 November 2026 | dropbear 2026.94 |