3 dbclient \- lightweight SSH2 client
9 .I l\fR:\fIh\fR:\fIr\fR] [\-R
10 .I l\fR:\fIh\fR:\fIr\fR] [\-l
18 .I [user1]@host1[/port1],[user2]@host2[/port2],...
22 is a SSH 2 client designed to be small enough to be used in small memory
23 environments, while still being functional and secure enough for general use.
35 Read the identity from file
39 .B \-L \fIlistenport\fR:\fIhost\fR:\fIport\fR
40 Local port forwarding.
43 on the local host through the SSH connection to port
48 .B \-R \fIlistenport\fR:\fIhost\fR:\fIport\fR
49 Remote port forwarding.
52 on the remote host through the SSH connection to port
70 Don't request a remote shell or run any commands. Any command arguments are ignored.
73 Fork into the background after authentication. A command argument (or -N) is required.
74 This is useful when using password authentication.
77 Allow non-local hosts to connect to forwarded ports. Applies to -L and -R
78 forwarded ports, though remote connections to -R forwarded ports may be limited
82 Always accept hostkeys if they are unknown. If a hostkey mismatch occurs the
83 connection will abort as normal.
86 Specify the per-channel receive window buffer size. Increasing this
87 may improve network performance at the expense of memory use. Use -h to see the
90 .B \-K \fItimeout_seconds
91 Ensure that traffic is transmitted at a certain interval in seconds. This is
92 useful for working around firewalls or routers that drop connections after
93 a certain period of inactivity. The trade-off is that a session may be
94 closed if there is a temporary lapse of network connectivity. A setting
95 if 0 disables keepalives.
97 .B \-I \fIidle_timeout
98 Disconnect the session if no traffic is transmitted or received for \fIidle_timeout\fR seconds.
100 .B \-J \fIproxy_command
101 Use the standard input/output of the program \fIproxy_command\fR rather than using
102 a normal TCP connection. A hostname should be still be provided, as this is used for
103 comparing saved hostkeys.
105 .B \-B \fIendhost:endport
106 "Netcat-alike" mode, where Dropbear will connect to the given host, then create a
107 forwarded connection to \fIendhost\fR. This will then be presented as dbclient's
108 standard input/output.
110 Dropbear will also allow multiple "hops" to be specified, separated by commas. In
111 this case a connection will be made to the first host, then a TCP forwarded
112 connection will be made through that to the second host, and so on. Hosts other than
113 the final destination will not see anything other than the encrypted SSH stream.
114 A port for a host can be specified with a slash (eg matt@martello/44 ).
115 This syntax can also be used with scp or rsync (specifying dbclient as the
116 ssh/rsh command). A file can be "bounced" through multiple SSH hops, eg
118 scp -S dbclient matt@martello,root@wrt,canyons:/tmp/dump .
120 Note that hostnames are resolved by the prior hop (so "canyons" would be resolved by the host "wrt")
121 in the example above, the same way as other -L TCP forwarded hosts are. Host keys are
122 checked locally based on the given hostname.
127 A password to use for remote authentication can be specified in the environment
128 variable DROPBEAR_PASSWORD. Care should be taken that the password is not
129 exposed to other users on a multi-user system, or stored in accessible files.
132 dbclient can use an external program to request a password from a user.
133 SSH_ASKPASS should be set to the path of a program that will return a password
134 on standard output. This program will only be used if either DISPLAY is set and
135 standard input is not a TTY, or the environment variable SSH_ASKPASS_ALWAYS is
138 Matt Johnston (matt@ucc.asn.au).
140 Mihnea Stoenescu wrote initial Dropbear client support
142 Gerrit Pape (pape@smarden.org) wrote this manual page.
144 dropbear(8), dropbearkey(8)
146 http://matt.ucc.asn.au/dropbear/dropbear.html