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authorColin Watson <cjwatson@debian.org>2016-02-29 12:15:15 +0000
committerColin Watson <cjwatson@debian.org>2016-02-29 12:15:15 +0000
commitc52a95cc4754e6630c96fe65ae0c65eb41d2c590 (patch)
tree793395934013923b7b2426382c0676edcd4be3d4 /ssh.1
parenteeff4de96f5d7365750dc56912c2c62b5c28db6b (diff)
parent72b061d4ba0f909501c595d709ea76e06b01e5c9 (diff)
Import openssh_7.2p1.orig.tar.gz
Diffstat (limited to 'ssh.1')
-rw-r--r--ssh.197
1 files changed, 42 insertions, 55 deletions
diff --git a/ssh.1 b/ssh.1
index 2ea0a2058..cc5334338 100644
--- a/ssh.1
+++ b/ssh.1
@@ -33,8 +33,8 @@
33.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 33.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
34.\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 34.\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
35.\" 35.\"
36.\" $OpenBSD: ssh.1,v 1.361 2015/07/20 18:44:12 millert Exp $ 36.\" $OpenBSD: ssh.1,v 1.369 2016/02/17 07:38:19 jmc Exp $
37.Dd $Mdocdate: July 20 2015 $ 37.Dd $Mdocdate: February 17 2016 $
38.Dt SSH 1 38.Dt SSH 1
39.Os 39.Os
40.Sh NAME 40.Sh NAME
@@ -58,7 +58,7 @@
58.Op Fl O Ar ctl_cmd 58.Op Fl O Ar ctl_cmd
59.Op Fl o Ar option 59.Op Fl o Ar option
60.Op Fl p Ar port 60.Op Fl p Ar port
61.Op Fl Q Cm cipher | cipher-auth | mac | kex | key | protocol-version 61.Op Fl Q Ar query_option
62.Op Fl R Ar address 62.Op Fl R Ar address
63.Op Fl S Ar ctl_path 63.Op Fl S Ar ctl_path
64.Op Fl W Ar host : Ns Ar port 64.Op Fl W Ar host : Ns Ar port
@@ -70,8 +70,7 @@
70.Nm 70.Nm
71(SSH client) is a program for logging into a remote machine and for 71(SSH client) is a program for logging into a remote machine and for
72executing commands on a remote machine. 72executing commands on a remote machine.
73It is intended to replace rlogin and rsh, 73It is intended to provide secure encrypted communications between
74and provide secure encrypted communications between
75two untrusted hosts over an insecure network. 74two untrusted hosts over an insecure network.
76X11 connections, arbitrary TCP ports and 75X11 connections, arbitrary TCP ports and
77.Ux Ns -domain 76.Ux Ns -domain
@@ -85,7 +84,7 @@ connects and logs into the specified
85name). 84name).
86The user must prove 85The user must prove
87his/her identity to the remote machine using one of several methods 86his/her identity to the remote machine using one of several methods
88depending on the protocol version used (see below). 87(see below).
89.Pp 88.Pp
90If 89If
91.Ar command 90.Ar command
@@ -304,6 +303,9 @@ It is possible to have multiple
304.Fl i 303.Fl i
305options (and multiple identities specified in 304options (and multiple identities specified in
306configuration files). 305configuration files).
306If no certificates have been explicitly specified by the
307.Cm CertificateFile
308directive,
307.Nm 309.Nm
308will also try to load certificate information from the filename obtained 310will also try to load certificate information from the filename obtained
309by appending 311by appending
@@ -400,17 +402,15 @@ in
400for details. 402for details.
401.Pp 403.Pp
402.It Fl m Ar mac_spec 404.It Fl m Ar mac_spec
403Additionally, for protocol version 2 a comma-separated list of MAC 405A comma-separated list of MAC (message authentication code) algorithms,
404(message authentication code) algorithms can 406specified in order of preference.
405be specified in order of preference.
406See the 407See the
407.Cm MACs 408.Cm MACs
408keyword for more information. 409keyword for more information.
409.Pp 410.Pp
410.It Fl N 411.It Fl N
411Do not execute a remote command. 412Do not execute a remote command.
412This is useful for just forwarding ports 413This is useful for just forwarding ports.
413(protocol version 2 only).
414.Pp 414.Pp
415.It Fl n 415.It Fl n
416Redirects stdin from 416Redirects stdin from
@@ -460,6 +460,7 @@ For full details of the options listed below, and their possible values, see
460.Xr ssh_config 5 . 460.Xr ssh_config 5 .
461.Pp 461.Pp
462.Bl -tag -width Ds -offset indent -compact 462.Bl -tag -width Ds -offset indent -compact
463.It AddKeysToAgent
463.It AddressFamily 464.It AddressFamily
464.It BatchMode 465.It BatchMode
465.It BindAddress 466.It BindAddress
@@ -468,6 +469,7 @@ For full details of the options listed below, and their possible values, see
468.It CanonicalizeHostname 469.It CanonicalizeHostname
469.It CanonicalizeMaxDots 470.It CanonicalizeMaxDots
470.It CanonicalizePermittedCNAMEs 471.It CanonicalizePermittedCNAMEs
472.It CertificateFile
471.It ChallengeResponseAuthentication 473.It ChallengeResponseAuthentication
472.It CheckHostIP 474.It CheckHostIP
473.It Cipher 475.It Cipher
@@ -550,7 +552,7 @@ Port to connect to on the remote host.
550This can be specified on a 552This can be specified on a
551per-host basis in the configuration file. 553per-host basis in the configuration file.
552.Pp 554.Pp
553.It Fl Q Cm cipher | cipher-auth | mac | kex | key | protocol-version 555.It Fl Q Ar query_option
554Queries 556Queries
555.Nm 557.Nm
556for the algorithms supported for the specified version 2. 558for the algorithms supported for the specified version 2.
@@ -564,7 +566,11 @@ The available features are:
564.Ar kex 566.Ar kex
565(key exchange algorithms), 567(key exchange algorithms),
566.Ar key 568.Ar key
567(key types) and 569(key types),
570.Ar key-cert
571(certificate key types),
572.Ar key-plain
573(non-certificate key types), and
568.Ar protocol-version 574.Ar protocol-version
569(supported SSH protocol versions). 575(supported SSH protocol versions).
570.Pp 576.Pp
@@ -656,8 +662,8 @@ for details.
656.Pp 662.Pp
657.It Fl s 663.It Fl s
658May be used to request invocation of a subsystem on the remote system. 664May be used to request invocation of a subsystem on the remote system.
659Subsystems are a feature of the SSH2 protocol which facilitate the use 665Subsystems facilitate the use of SSH
660of SSH as a secure transport for other applications (eg.\& 666as a secure transport for other applications (e.g.\&
661.Xr sftp 1 ) . 667.Xr sftp 1 ) .
662The subsystem is specified as the remote command. 668The subsystem is specified as the remote command.
663.Pp 669.Pp
@@ -702,7 +708,6 @@ Implies
702.Cm ExitOnForwardFailure 708.Cm ExitOnForwardFailure
703and 709and
704.Cm ClearAllForwardings . 710.Cm ClearAllForwardings .
705Works with Protocol version 2 only.
706.Pp 711.Pp
707.It Fl w Xo 712.It Fl w Xo
708.Ar local_tun Ns Op : Ns Ar remote_tun 713.Ar local_tun Ns Op : Ns Ar remote_tun
@@ -787,15 +792,10 @@ or the
787and 792and
788.Fl 2 793.Fl 2
789options (see above). 794options (see above).
790Both protocols support similar authentication methods, 795Protocol 1 should not be used
791but protocol 2 is the default since 796and is only offered to support legacy devices.
792it provides additional mechanisms for confidentiality 797It suffers from a number of cryptographic weaknesses
793(the traffic is encrypted using AES, 3DES, Blowfish, CAST128, or Arcfour) 798and doesn't support many of the advanced features available for protocol 2.
794and integrity (hmac-md5, hmac-sha1,
795hmac-sha2-256, hmac-sha2-512,
796umac-64, umac-128, hmac-ripemd160).
797Protocol 1 lacks a strong mechanism for ensuring the
798integrity of the connection.
799.Pp 799.Pp
800The methods available for authentication are: 800The methods available for authentication are:
801GSSAPI-based authentication, 801GSSAPI-based authentication,
@@ -804,8 +804,9 @@ public key authentication,
804challenge-response authentication, 804challenge-response authentication,
805and password authentication. 805and password authentication.
806Authentication methods are tried in the order specified above, 806Authentication methods are tried in the order specified above,
807though protocol 2 has a configuration option to change the default order: 807though
808.Cm PreferredAuthentications . 808.Cm PreferredAuthentications
809can be used to change the default order.
809.Pp 810.Pp
810Host-based authentication works as follows: 811Host-based authentication works as follows:
811If the machine the user logs in from is listed in 812If the machine the user logs in from is listed in
@@ -849,8 +850,6 @@ The server knows the public key, and only the user knows the private key.
849.Nm 850.Nm
850implements public key authentication protocol automatically, 851implements public key authentication protocol automatically,
851using one of the DSA, ECDSA, Ed25519 or RSA algorithms. 852using one of the DSA, ECDSA, Ed25519 or RSA algorithms.
852Protocol 1 is restricted to using only RSA keys,
853but protocol 2 may use any.
854The HISTORY section of 853The HISTORY section of
855.Xr ssl 8 854.Xr ssl 8
856contains a brief discussion of the DSA and RSA algorithms. 855contains a brief discussion of the DSA and RSA algorithms.
@@ -872,26 +871,26 @@ This stores the private key in
872.Pa ~/.ssh/identity 871.Pa ~/.ssh/identity
873(protocol 1), 872(protocol 1),
874.Pa ~/.ssh/id_dsa 873.Pa ~/.ssh/id_dsa
875(protocol 2 DSA), 874(DSA),
876.Pa ~/.ssh/id_ecdsa 875.Pa ~/.ssh/id_ecdsa
877(protocol 2 ECDSA), 876(ECDSA),
878.Pa ~/.ssh/id_ed25519 877.Pa ~/.ssh/id_ed25519
879(protocol 2 Ed25519), 878(Ed25519),
880or 879or
881.Pa ~/.ssh/id_rsa 880.Pa ~/.ssh/id_rsa
882(protocol 2 RSA) 881(RSA)
883and stores the public key in 882and stores the public key in
884.Pa ~/.ssh/identity.pub 883.Pa ~/.ssh/identity.pub
885(protocol 1), 884(protocol 1),
886.Pa ~/.ssh/id_dsa.pub 885.Pa ~/.ssh/id_dsa.pub
887(protocol 2 DSA), 886(DSA),
888.Pa ~/.ssh/id_ecdsa.pub 887.Pa ~/.ssh/id_ecdsa.pub
889(protocol 2 ECDSA), 888(ECDSA),
890.Pa ~/.ssh/id_ed25519.pub 889.Pa ~/.ssh/id_ed25519.pub
891(protocol 2 Ed25519), 890(Ed25519),
892or 891or
893.Pa ~/.ssh/id_rsa.pub 892.Pa ~/.ssh/id_rsa.pub
894(protocol 2 RSA) 893(RSA)
895in the user's home directory. 894in the user's home directory.
896The user should then copy the public key 895The user should then copy the public key
897to 896to
@@ -919,14 +918,16 @@ The most convenient way to use public key or certificate authentication
919may be with an authentication agent. 918may be with an authentication agent.
920See 919See
921.Xr ssh-agent 1 920.Xr ssh-agent 1
921and (optionally) the
922.Cm AddKeysToAgent
923directive in
924.Xr ssh_config 5
922for more information. 925for more information.
923.Pp 926.Pp
924Challenge-response authentication works as follows: 927Challenge-response authentication works as follows:
925The server sends an arbitrary 928The server sends an arbitrary
926.Qq challenge 929.Qq challenge
927text, and prompts for a response. 930text, and prompts for a response.
928Protocol 2 allows multiple challenges and responses;
929protocol 1 is restricted to just one challenge/response.
930Examples of challenge-response authentication include 931Examples of challenge-response authentication include
931.Bx 932.Bx
932Authentication (see 933Authentication (see
@@ -1025,7 +1026,7 @@ at logout when waiting for forwarded connection / X11 sessions to terminate.
1025Display a list of escape characters. 1026Display a list of escape characters.
1026.It Cm ~B 1027.It Cm ~B
1027Send a BREAK to the remote system 1028Send a BREAK to the remote system
1028(only useful for SSH protocol version 2 and if the peer supports it). 1029(only useful if the peer supports it).
1029.It Cm ~C 1030.It Cm ~C
1030Open command line. 1031Open command line.
1031Currently this allows the addition of port forwardings using the 1032Currently this allows the addition of port forwardings using the
@@ -1058,7 +1059,7 @@ Basic help is available, using the
1058option. 1059option.
1059.It Cm ~R 1060.It Cm ~R
1060Request rekeying of the connection 1061Request rekeying of the connection
1061(only useful for SSH protocol version 2 and if the peer supports it). 1062(only useful if the peer supports it).
1062.It Cm ~V 1063.It Cm ~V
1063Decrease the verbosity 1064Decrease the verbosity
1064.Pq Ic LogLevel 1065.Pq Ic LogLevel
@@ -1526,20 +1527,6 @@ The file format and configuration options are described in
1526.It Pa /etc/ssh/ssh_host_rsa_key 1527.It Pa /etc/ssh/ssh_host_rsa_key
1527These files contain the private parts of the host keys 1528These files contain the private parts of the host keys
1528and are used for host-based authentication. 1529and are used for host-based authentication.
1529If protocol version 1 is used,
1530.Nm
1531must be setuid root, since the host key is readable only by root.
1532For protocol version 2,
1533.Nm
1534uses
1535.Xr ssh-keysign 8
1536to access the host keys,
1537eliminating the requirement that
1538.Nm
1539be setuid root when host-based authentication is used.
1540By default
1541.Nm
1542is not setuid root.
1543.Pp 1530.Pp
1544.It Pa /etc/ssh/ssh_known_hosts 1531.It Pa /etc/ssh/ssh_known_hosts
1545Systemwide list of known host keys. 1532Systemwide list of known host keys.