summaryrefslogtreecommitdiff
path: root/sshd.8
diff options
context:
space:
mode:
authorDamien Miller <djm@mindrot.org>2006-03-15 11:33:56 +1100
committerDamien Miller <djm@mindrot.org>2006-03-15 11:33:56 +1100
commitd8702e865d1e0107d50dc0296b22dc0b788d5a0a (patch)
tree8be7891577f589f573adb9eed1a23ec0a9d835d9 /sshd.8
parentc8f61cf1996a7374de465d8e2fda93dec34364a2 (diff)
- jmc@cvs.openbsd.org 2006/02/13 11:27:25
[sshd.8] sort FILES and use a -compact list;
Diffstat (limited to 'sshd.8')
-rw-r--r--sshd.8284
1 files changed, 154 insertions, 130 deletions
diff --git a/sshd.8 b/sshd.8
index 0ad133d0d..e56b422a6 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 1.222 2006/02/13 11:08:43 jmc Exp $ 37.\" $OpenBSD: sshd.8,v 1.223 2006/02/13 11:27:25 jmc Exp $
38.Dd September 25, 1999 38.Dd September 25, 1999
39.Dt SSHD 8 39.Dt SSHD 8
40.Os 40.Os
@@ -591,77 +591,8 @@ cvs.example.net,192.0.2.10 ssh-rsa AAAA1234.....=
591AAAA1234.....= 591AAAA1234.....=
592.Ed 592.Ed
593.Sh FILES 593.Sh FILES
594.Bl -tag -width Ds 594.Bl -tag -width Ds -compact
595.It Pa /etc/ssh/sshd_config 595.It ~/.hushlogin
596Contains configuration data for
597.Nm sshd .
598The file format and configuration options are described in
599.Xr sshd_config 5 .
600.It Pa /etc/ssh/ssh_host_key, /etc/ssh/ssh_host_dsa_key, /etc/ssh/ssh_host_rsa_key
601These three files contain the private parts of the host keys.
602These files should only be owned by root, readable only by root, and not
603accessible to others.
604Note that
605.Nm
606does not start if this file is group/world-accessible.
607.It Pa /etc/ssh/ssh_host_key.pub, /etc/ssh/ssh_host_dsa_key.pub, /etc/ssh/ssh_host_rsa_key.pub
608These three files contain the public parts of the host keys.
609These files should be world-readable but writable only by
610root.
611Their contents should match the respective private parts.
612These files are not
613really used for anything; they are provided for the convenience of
614the user so their contents can be copied to known hosts files.
615These files are created using
616.Xr ssh-keygen 1 .
617.It Pa /etc/moduli
618Contains Diffie-Hellman groups used for the "Diffie-Hellman Group Exchange".
619The file format is described in
620.Xr moduli 5 .
621.It Pa /var/empty
622.Xr chroot 2
623directory used by
624.Nm
625during privilege separation in the pre-authentication phase.
626The directory should not contain any files and must be owned by root
627and not group or world-writable.
628.It Pa /var/run/sshd.pid
629Contains the process ID of the
630.Nm
631listening for connections (if there are several daemons running
632concurrently for different ports, this contains the process ID of the one
633started last).
634The content of this file is not sensitive; it can be world-readable.
635.It Pa ~/.ssh/authorized_keys
636Lists the public keys (RSA or DSA) that can be used to log into the user's account.
637This file must be readable by root (which may on some machines imply
638it being world-readable if the user's home directory resides on an NFS
639volume).
640It is recommended that it not be accessible by others.
641The format of this file is described above.
642Users will place the contents of their
643.Pa identity.pub ,
644.Pa id_dsa.pub
645and/or
646.Pa id_rsa.pub
647files into this file, as described in
648.Xr ssh-keygen 1 .
649.It Pa "/etc/ssh/ssh_known_hosts", "~/.ssh/known_hosts"
650These files are consulted when using rhosts with RSA host
651authentication or protocol version 2 hostbased authentication
652to check the public key of the host.
653The key must be listed in one of these files to be accepted.
654The client uses the same files
655to verify that it is connecting to the correct remote host.
656These files should be writable only by root/the owner.
657.Pa /etc/ssh/ssh_known_hosts
658should be world-readable, and
659.Pa ~/.ssh/known_hosts
660can, but need not be, world-readable.
661.It Pa /etc/motd
662See
663.Xr motd 5 .
664.It Pa ~/.hushlogin
665This file is used to suppress printing the last login time and 596This file is used to suppress printing the last login time and
666.Pa /etc/motd , 597.Pa /etc/motd ,
667if 598if
@@ -672,19 +603,8 @@ respectively,
672are enabled. 603are enabled.
673It does not suppress printing of the banner specified by 604It does not suppress printing of the banner specified by
674.Cm Banner . 605.Cm Banner .
675.It Pa /etc/nologin 606.Pp
676If this file exists, 607.It ~/.rhosts
677.Nm
678refuses to let anyone except root log in.
679The contents of the file
680are displayed to anyone trying to log in, and non-root connections are
681refused.
682The file should be world-readable.
683.It Pa /etc/hosts.allow, /etc/hosts.deny
684Access controls that should be enforced by tcp-wrappers are defined here.
685Further details are described in
686.Xr hosts_access 5 .
687.It Pa ~/.rhosts
688This file is used during 608This file is used during
689.Cm RhostsRSAAuthentication 609.Cm RhostsRSAAuthentication
690and 610and
@@ -702,56 +622,30 @@ It is also possible to use netgroups in the file.
702Either host or user 622Either host or user
703name may be of the form +@groupname to specify all hosts or all users 623name may be of the form +@groupname to specify all hosts or all users
704in the group. 624in the group.
705.It Pa ~/.shosts 625.Pp
626.It ~/.shosts
706For ssh, 627For ssh,
707this file is exactly the same as for 628this file is exactly the same as for
708.Pa .rhosts . 629.Pa .rhosts .
709However, this file is 630However, this file is
710not used by rlogin and rshd, so using this permits access using SSH only. 631not used by rlogin and rshd, so using this permits access using SSH only.
711.It Pa /etc/hosts.equiv
712This file is used during
713.Cm RhostsRSAAuthentication
714and
715.Cm HostbasedAuthentication
716authentication.
717In the simplest form, this file contains host names, one per line.
718Users on
719those hosts are permitted to log in without a password, provided they
720have the same user name on both machines.
721The host name may also be
722followed by a user name; such users are permitted to log in as
723.Em any
724user on this machine (except root).
725Additionally, the syntax
726.Dq +@group
727can be used to specify netgroups.
728Negated entries start with
729.Ql \&- .
730.Pp
731If the client host/user is successfully matched in this file, login is
732automatically permitted provided the client and server user names are the
733same.
734Additionally, successful client host key authentication is required.
735This file must be writable only by root; it is recommended
736that it be world-readable.
737.Pp 632.Pp
738.Sy "Warning: It is almost never a good idea to use user names in" 633.It ~/.ssh/authorized_keys
739.Pa hosts.equiv . 634Lists the public keys (RSA or DSA) that can be used to log into the user's account.
740Beware that it really means that the named user(s) can log in as 635This file must be readable by root (which may on some machines imply
741.Em anybody , 636it being world-readable if the user's home directory resides on an NFS
742which includes bin, daemon, adm, and other accounts that own critical 637volume).
743binaries and directories. 638It is recommended that it not be accessible by others.
744Using a user name practically grants the user root access. 639The format of this file is described above.
745The only valid use for user names that I can think 640Users will place the contents of their
746of is in negative entries. 641.Pa identity.pub ,
642.Pa id_dsa.pub
643and/or
644.Pa id_rsa.pub
645files into this file, as described in
646.Xr ssh-keygen 1 .
747.Pp 647.Pp
748Note that this warning also applies to rsh/rlogin. 648.It ~/.ssh/environment
749.It Pa /etc/shosts.equiv
750This is processed exactly as
751.Pa /etc/hosts.equiv .
752However, this file may be useful in environments that want to run both
753rsh/rlogin and ssh.
754.It Pa ~/.ssh/environment
755This file is read into the environment at login (if it exists). 649This file is read into the environment at login (if it exists).
756It can only contain empty lines, comment lines (that start with 650It can only contain empty lines, comment lines (that start with
757.Ql # ) , 651.Ql # ) ,
@@ -762,7 +656,22 @@ Environment processing is disabled by default and is
762controlled via the 656controlled via the
763.Cm PermitUserEnvironment 657.Cm PermitUserEnvironment
764option. 658option.
765.It Pa ~/.ssh/rc 659.Pp
660.It ~/.ssh/known_hosts
661.It /etc/ssh/ssh_known_hosts
662These files are consulted when using rhosts with RSA host
663authentication or protocol version 2 hostbased authentication
664to check the public key of the host.
665The key must be listed in one of these files to be accepted.
666The client uses the same files
667to verify that it is connecting to the correct remote host.
668These files should be writable only by root/the owner.
669.Pa /etc/ssh/ssh_known_hosts
670should be world-readable, and
671.Pa ~/.ssh/known_hosts
672can, but need not be, world-readable.
673.Pp
674.It ~/.ssh/rc
766If this file exists, it is run with 675If this file exists, it is run with
767.Pa /bin/sh 676.Pa /bin/sh
768after reading the 677after reading the
@@ -805,12 +714,127 @@ does not exist either, xauth is used to add the cookie.
805.Pp 714.Pp
806This file should be writable only by the user, and need not be 715This file should be writable only by the user, and need not be
807readable by anyone else. 716readable by anyone else.
808.It Pa /etc/ssh/sshrc 717.Pp
718.It /etc/hosts.allow
719.It /etc/hosts.deny
720Access controls that should be enforced by tcp-wrappers are defined here.
721Further details are described in
722.Xr hosts_access 5 .
723.Pp
724.It /etc/hosts.equiv
725This file is used during
726.Cm RhostsRSAAuthentication
727and
728.Cm HostbasedAuthentication
729authentication.
730In the simplest form, this file contains host names, one per line.
731Users on
732those hosts are permitted to log in without a password, provided they
733have the same user name on both machines.
734The host name may also be
735followed by a user name; such users are permitted to log in as
736.Em any
737user on this machine (except root).
738Additionally, the syntax
739.Dq +@group
740can be used to specify netgroups.
741Negated entries start with
742.Ql \&- .
743.Pp
744If the client host/user is successfully matched in this file, login is
745automatically permitted provided the client and server user names are the
746same.
747Additionally, successful client host key authentication is required.
748This file must be writable only by root; it is recommended
749that it be world-readable.
750.Pp
751.Sy "Warning: It is almost never a good idea to use user names in"
752.Pa hosts.equiv .
753Beware that it really means that the named user(s) can log in as
754.Em anybody ,
755which includes bin, daemon, adm, and other accounts that own critical
756binaries and directories.
757Using a user name practically grants the user root access.
758The only valid use for user names that I can think
759of is in negative entries.
760.Pp
761Note that this warning also applies to rsh/rlogin.
762.Pp
763.It /etc/moduli
764Contains Diffie-Hellman groups used for the "Diffie-Hellman Group Exchange".
765The file format is described in
766.Xr moduli 5 .
767.Pp
768.It /etc/motd
769See
770.Xr motd 5 .
771.Pp
772.It /etc/nologin
773If this file exists,
774.Nm
775refuses to let anyone except root log in.
776The contents of the file
777are displayed to anyone trying to log in, and non-root connections are
778refused.
779The file should be world-readable.
780.Pp
781.It /etc/shosts.equiv
782This is processed exactly as
783.Pa /etc/hosts.equiv .
784However, this file may be useful in environments that want to run both
785rsh/rlogin and ssh.
786.Pp
787.It /etc/ssh/ssh_host_key
788.It /etc/ssh/ssh_host_dsa_key
789.It /etc/ssh/ssh_host_rsa_key
790These three files contain the private parts of the host keys.
791These files should only be owned by root, readable only by root, and not
792accessible to others.
793Note that
794.Nm
795does not start if this file is group/world-accessible.
796.Pp
797.It /etc/ssh/ssh_host_key.pub
798.It /etc/ssh/ssh_host_dsa_key.pub
799.It /etc/ssh/ssh_host_rsa_key.pub
800These three files contain the public parts of the host keys.
801These files should be world-readable but writable only by
802root.
803Their contents should match the respective private parts.
804These files are not
805really used for anything; they are provided for the convenience of
806the user so their contents can be copied to known hosts files.
807These files are created using
808.Xr ssh-keygen 1 .
809.Pp
810.It /etc/ssh/sshd_config
811Contains configuration data for
812.Nm sshd .
813The file format and configuration options are described in
814.Xr sshd_config 5 .
815.Pp
816.It /etc/ssh/sshrc
809Like 817Like
810.Pa ~/.ssh/rc . 818.Pa ~/.ssh/rc .
811This can be used to specify 819This can be used to specify
812machine-specific login-time initializations globally. 820machine-specific login-time initializations globally.
813This file should be writable only by root, and should be world-readable. 821This file should be writable only by root, and should be world-readable.
822.Pp
823.It /var/empty
824.Xr chroot 2
825directory used by
826.Nm
827during privilege separation in the pre-authentication phase.
828The directory should not contain any files and must be owned by root
829and not group or world-writable.
830.Pp
831.It /var/run/sshd.pid
832Contains the process ID of the
833.Nm
834listening for connections (if there are several daemons running
835concurrently for different ports, this contains the process ID of the one
836started last).
837The content of this file is not sensitive; it can be world-readable.
814.El 838.El
815.Sh SEE ALSO 839.Sh SEE ALSO
816.Xr scp 1 , 840.Xr scp 1 ,