summaryrefslogtreecommitdiff
path: root/sshd.8
diff options
context:
space:
mode:
Diffstat (limited to 'sshd.8')
-rw-r--r--sshd.852
1 files changed, 40 insertions, 12 deletions
diff --git a/sshd.8 b/sshd.8
index c5949dc1a..99e62173c 100644
--- a/sshd.8
+++ b/sshd.8
@@ -34,7 +34,7 @@
34.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 34.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
35.\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 35.\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
36.\" 36.\"
37.\" $OpenBSD: sshd.8,v 1.201 2004/05/02 11:54:31 dtucker Exp $ 37.\" $OpenBSD: sshd.8,v 1.206 2005/03/01 14:59:49 jmc Exp $
38.Dd September 25, 1999 38.Dd September 25, 1999
39.Dt SSHD 8 39.Dt SSHD 8
40.Os 40.Os
@@ -106,8 +106,6 @@ to use from those offered by the server.
106Next, the server and the client enter an authentication dialog. 106Next, the server and the client enter an authentication dialog.
107The client tries to authenticate itself using 107The client tries to authenticate itself using
108.Em .rhosts 108.Em .rhosts
109authentication,
110.Em .rhosts
111authentication combined with RSA host 109authentication combined with RSA host
112authentication, RSA challenge-response authentication, or password 110authentication, RSA challenge-response authentication, or password
113based authentication. 111based authentication.
@@ -135,11 +133,6 @@ or
135.Ql \&*NP\&* 133.Ql \&*NP\&*
136). 134).
137.Pp 135.Pp
138.Em rhosts
139authentication is normally disabled
140because it is fundamentally insecure, but can be enabled in the server
141configuration file if desired.
142System security is not improved unless
143.Nm rshd , 136.Nm rshd ,
144.Nm rlogind , 137.Nm rlogind ,
145and 138and
@@ -430,7 +423,9 @@ or
430.Dq ssh-rsa . 423.Dq ssh-rsa .
431.Pp 424.Pp
432Note that lines in this file are usually several hundred bytes long 425Note that lines in this file are usually several hundred bytes long
433(because of the size of the public key encoding). 426(because of the size of the public key encoding) up to a limit of
4278 kilobytes, which permits DSA keys up to 8 kilobits and RSA
428keys up to 16 kilobits.
434You don't want to type them in; instead, copy the 429You don't want to type them in; instead, copy the
435.Pa identity.pub , 430.Pa identity.pub ,
436.Pa id_dsa.pub 431.Pa id_dsa.pub
@@ -561,6 +556,14 @@ to indicate negation: if the host name matches a negated
561pattern, it is not accepted (by that line) even if it matched another 556pattern, it is not accepted (by that line) even if it matched another
562pattern on the line. 557pattern on the line.
563.Pp 558.Pp
559Alternately, hostnames may be stored in a hashed form which hides host names
560and addresses should the file's contents be disclosed.
561Hashed hostnames start with a
562.Ql |
563character.
564Only one hashed hostname may appear on a single line and none of the above
565negation or wildcard operators may be applied.
566.Pp
564Bits, exponent, and modulus are taken directly from the RSA host key; they 567Bits, exponent, and modulus are taken directly from the RSA host key; they
565can be obtained, e.g., from 568can be obtained, e.g., from
566.Pa /etc/ssh/ssh_host_key.pub . 569.Pa /etc/ssh/ssh_host_key.pub .
@@ -592,6 +595,11 @@ and adding the host names at the front.
592closenet,...,130.233.208.41 1024 37 159...93 closenet.hut.fi 595closenet,...,130.233.208.41 1024 37 159...93 closenet.hut.fi
593cvs.openbsd.org,199.185.137.3 ssh-rsa AAAA1234.....= 596cvs.openbsd.org,199.185.137.3 ssh-rsa AAAA1234.....=
594.Ed 597.Ed
598.Bd -literal
599# A hashed hostname
600|1|JfKTdBh7rNbXkVAQCRp4OQoPfmI=|USECr3SWf1JUPsms5AqfD5QfxkM= ssh-rsa
601AAAA1234.....=
602.Ed
595.Sh FILES 603.Sh FILES
596.Bl -tag -width Ds 604.Bl -tag -width Ds
597.It Pa /etc/ssh/sshd_config 605.It Pa /etc/ssh/sshd_config
@@ -660,6 +668,20 @@ These files should be writable only by root/the owner.
660should be world-readable, and 668should be world-readable, and
661.Pa $HOME/.ssh/known_hosts 669.Pa $HOME/.ssh/known_hosts
662can, but need not be, world-readable. 670can, but need not be, world-readable.
671.It Pa /etc/motd
672See
673.Xr motd 5 .
674.It Pa $HOME/.hushlogin
675This file is used to suppress printing the last login time and
676.Pa /etc/motd ,
677if
678.Cm PrintLastLog
679and
680.Cm PrintMotd ,
681respectively,
682are enabled.
683It does not suppress printing of the banner specified by
684.Cm Banner .
663.It Pa /etc/nologin 685.It Pa /etc/nologin
664If this file exists, 686If this file exists,
665.Nm 687.Nm
@@ -673,7 +695,11 @@ Access controls that should be enforced by tcp-wrappers are defined here.
673Further details are described in 695Further details are described in
674.Xr hosts_access 5 . 696.Xr hosts_access 5 .
675.It Pa $HOME/.rhosts 697.It Pa $HOME/.rhosts
676This file contains host-username pairs, separated by a space, one per 698This file is used during
699.Cm RhostsRSAAuthentication
700and
701.Cm HostbasedAuthentication
702and contains host-username pairs, separated by a space, one per
677line. 703line.
678The given user on the corresponding host is permitted to log in 704The given user on the corresponding host is permitted to log in
679without a password. 705without a password.
@@ -694,7 +720,9 @@ However, this file is
694not used by rlogin and rshd, so using this permits access using SSH only. 720not used by rlogin and rshd, so using this permits access using SSH only.
695.It Pa /etc/hosts.equiv 721.It Pa /etc/hosts.equiv
696This file is used during 722This file is used during
697.Em rhosts 723.Cm RhostsRSAAuthentication
724and
725.Cm HostbasedAuthentication
698authentication. 726authentication.
699In the simplest form, this file contains host names, one per line. 727In the simplest form, this file contains host names, one per line.
700Users on 728Users on
@@ -713,7 +741,7 @@ Negated entries start with
713If the client host/user is successfully matched in this file, login is 741If the client host/user is successfully matched in this file, login is
714automatically permitted provided the client and server user names are the 742automatically permitted provided the client and server user names are the
715same. 743same.
716Additionally, successful RSA host authentication is normally required. 744Additionally, successful client host key authentication is required.
717This file must be writable only by root; it is recommended 745This file must be writable only by root; it is recommended
718that it be world-readable. 746that it be world-readable.
719.Pp 747.Pp