-.\" $OpenBSD: ssh-keyscan.1,v 1.17 2003/06/10 09:12:11 jmc Exp $
+.\" $OpenBSD: ssh-keyscan.1,v 1.12 2001/09/05 06:23:07 deraadt Exp $
.\"
.\" Copyright 1995, 1996 by David Mazieres <dm@lcs.mit.edu>.
.\"
.Nd gather ssh public keys
.Sh SYNOPSIS
.Nm ssh-keyscan
-.Bk -words
.Op Fl v46
.Op Fl p Ar port
.Op Fl T Ar timeout
.Op Fl f Ar file
.Op Ar host | addrlist namelist
.Op Ar ...
-.Ek
.Sh DESCRIPTION
.Nm
is a utility for gathering the public ssh host keys of a number of
-hosts.
-It was designed to aid in building and verifying
+hosts. It was designed to aid in building and verifying
.Pa ssh_known_hosts
files.
.Nm
.Pp
.Nm
uses non-blocking socket I/O to contact as many hosts as possible in
-parallel, so it is very efficient.
-The keys from a domain of 1,000
+parallel, so it is very efficient. The keys from a domain of 1,000
hosts can be collected in tens of seconds, even when some of those
-hosts are down or do not run ssh.
-For scanning, one does not need
+hosts are down or do not run ssh. For scanning, one does not need
login access to the machines that are being scanned, nor does the
scanning process involve any encryption.
.Pp
.It Fl p Ar port
Port to connect to on the remote host.
.It Fl T Ar timeout
-Set the timeout for connection attempts.
-If
+Set the timeout for connection attempts. If
.Pa timeout
seconds have elapsed since a connection was initiated to a host or since the
last time anything was read from that host, then the connection is
-closed and the host in question considered unavailable.
-Default is 5 seconds.
+closed and the host in question considered unavailable. Default is 5
+seconds.
.It Fl t Ar type
Specifies the type of the key to fetch from the scanned hosts.
The possible values are
.Nm
can help in the detection of tampered keyfiles or man in the middle
attacks which have begun after the ssh_known_hosts file was created.
+.Sh EXAMPLES
+.Pp
+Print the
+.Pa rsa1
+host key for machine
+.Pa hostname :
+.Bd -literal
+ssh-keyscan hostname
+.Ed
+.Pp
+Find all hosts from the file
+.Pa ssh_hosts
+which have new or different keys from those in the sorted file
+.Pa ssh_known_hosts :
+.Bd -literal
+ssh-keyscan -t rsa,dsa -f ssh_hosts | \e\
+ sort -u - ssh_known_hosts | diff ssh_known_hosts -
+.Ed
.Sh FILES
.Pa Input format:
.Bd -literal
is either
.Dq ssh-rsa
or
-.Dq ssh-dss .
-.Pp
-.Pa /etc/ssh/ssh_known_hosts
-.Sh EXAMPLES
-Print the
-.Pa rsa1
-host key for machine
-.Pa hostname :
-.Bd -literal
-$ ssh-keyscan hostname
-.Ed
+.Dq ssh-dsa .
.Pp
-Find all hosts from the file
-.Pa ssh_hosts
-which have new or different keys from those in the sorted file
-.Pa ssh_known_hosts :
-.Bd -literal
-$ ssh-keyscan -t rsa,dsa -f ssh_hosts | \e
- sort -u - ssh_known_hosts | diff ssh_known_hosts -
-.Ed
+.Pa /etc/ssh_known_hosts
+.Sh BUGS
+It generates "Connection closed by remote host" messages on the consoles
+of all the machines it scans if the server is older than version 2.9.
+This is because it opens a connection to the ssh port, reads the public
+key, and drops the connection as soon as it gets the key.
.Sh SEE ALSO
.Xr ssh 1 ,
.Xr sshd 8
.Sh AUTHORS
-.An David Mazieres Aq dm@lcs.mit.edu
+David Mazieres <dm@lcs.mit.edu>
wrote the initial version, and
-.An Wayne Davison Aq wayned@users.sourceforge.net
+Wayne Davison <wayned@users.sourceforge.net>
added support for protocol version 2.
-.Sh BUGS
-It generates "Connection closed by remote host" messages on the consoles
-of all the machines it scans if the server is older than version 2.9.
-This is because it opens a connection to the ssh port, reads the public
-key, and drops the connection as soon as it gets the key.
andersk / gssapi-openssh.git / blobdiff