-.\" $OpenBSD: ssh-agent.1,v 1.22 2001/03/02 18:54:31 deraadt Exp $
+.\" $OpenBSD: ssh-agent.1,v 1.36 2003/01/21 18:14:36 marc Exp $
.\"
.\" Author: Tatu Ylonen <ylo@cs.hut.fi>
.\" Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
.Nd authentication agent
.Sh SYNOPSIS
.Nm ssh-agent
-.Ar command
-.Ar args ...
-.Nm ssh-agent
+.Op Fl a Ar bind_address
.Op Fl c Li | Fl s
+.Op Fl t Ar life
+.Op Fl d
+.Op Ar command Op Ar args ...
.Nm ssh-agent
+.Op Fl c Li | Fl s
.Fl k
.Sh DESCRIPTION
.Nm
.Pp
The options are as follows:
.Bl -tag -width Ds
+.It Fl a Ar bind_address
+Bind the agent to the unix-domain socket
+.Ar bind_address .
+The default is
+.Pa /tmp/ssh-XXXXXXXX/agent.<ppid> .
.It Fl c
Generate C-shell commands on
.Dv stdout .
Kill the current agent (given by the
.Ev SSH_AGENT_PID
environment variable).
+.It Fl t Ar life
+Set a default value for the maximum lifetime of identities added to the agent.
+The lifetime may be specified in seconds or in a time format specified in
+.Xr sshd 8 .
+A lifetime specified for an identity with
+.Xr ssh-add 1
+overrides this value.
+Without this option the default maximum lifetime is forever.
+.It Fl d
+Debug mode. When this option is specified
+.Nm
+will not fork.
.El
.Pp
If a commandline is given, this is executed as a subprocess of the agent.
.Xr ssh-add 1 .
When executed without arguments,
.Xr ssh-add 1
-adds the
-.Pa $HOME/.ssh/identity
-file.
+adds the files
+.Pa $HOME/.ssh/id_rsa ,
+.Pa $HOME/.ssh/id_dsa
+and
+.Pa $HOME/.ssh/identity .
If the identity has a passphrase,
.Xr ssh-add 1
asks for the passphrase (using a small X11 application if running
identities anywhere in the network in a secure way.
.Pp
There are two main ways to get an agent setup:
-Either you let the agent
-start a new subcommand into which some environment variables are exported, or
-you let the agent print the needed shell commands (either
+Either the agent starts a new subcommand into which some environment
+variables are exported, or the agent prints the needed shell commands
+(either
.Xr sh 1
or
.Xr csh 1
syntax can be generated) which can be evalled in the calling shell.
Later
.Xr ssh 1
-look at these variables and use them to establish a connection to the agent.
+looks at these variables and uses them to establish a connection to the agent.
+.Pp
+The agent will never send a private key over its request channel.
+Instead, operations that require a private key will be performed
+by the agent, and the result will be returned to the requester.
+This way, private keys are not exposed to clients using the agent.
.Pp
A unix-domain socket is created
-.Pq Pa /tmp/ssh-XXXXXXXX/agent.<pid> ,
and the name of this socket is stored in the
.Ev SSH_AUTH_SOCK
environment
.Pp
The
.Ev SSH_AGENT_PID
-environment variable holds the agent's PID.
+environment variable holds the agent's process ID.
.Pp
The agent exits automatically when the command given on the command
line terminates.
.Sh FILES
.Bl -tag -width Ds
.It Pa $HOME/.ssh/identity
-Contains the RSA authentication identity of the user.
-This file should not be readable by anyone but the user.
-It is possible to
-specify a passphrase when generating the key; that passphrase will be
-used to encrypt the private part of this file.
-This file is not used by
-.Nm
-but is normally added to the agent using
-.Xr ssh-add 1
-at login time.
+Contains the protocol version 1 RSA authentication identity of the user.
.It Pa $HOME/.ssh/id_dsa
-Contains the DSA authentication identity of the user.
-.It Pa /tmp/ssh-XXXXXXXX/agent.<pid>
+Contains the protocol version 2 DSA authentication identity of the user.
+.It Pa $HOME/.ssh/id_rsa
+Contains the protocol version 2 RSA authentication identity of the user.
+.It Pa /tmp/ssh-XXXXXXXX/agent.<ppid>
Unix-domain sockets used to contain the connection to the
authentication agent.
These sockets should only be readable by the owner.
andersk / openssh.git / blobdiff