From 942da039d2a05e6f491883f50b516175a6dbb20f Mon Sep 17 00:00:00 2001 From: Damien Miller Date: Fri, 18 Aug 2000 13:59:06 +1000 Subject: - (djm) OpenBSD CVS changes: - markus@cvs.openbsd.org 2000/07/22 03:14:37 [servconf.c servconf.h sshd.8 sshd.c sshd_config] random early drop; ok theo, niels - deraadt@cvs.openbsd.org 2000/07/26 11:46:51 [ssh.1] typo - deraadt@cvs.openbsd.org 2000/08/01 11:46:11 [sshd.8] many fixes from pepper@mail.reppep.com - provos@cvs.openbsd.org 2000/08/01 13:01:42 [Makefile.in util.c aux.c] rename aux.c to util.c to help with cygwin port - deraadt@cvs.openbsd.org 2000/08/02 00:23:31 [authfd.c] correct sun_len; Alexander@Leidinger.net - provos@cvs.openbsd.org 2000/08/02 10:27:17 [readconf.c sshd.8] disable kerberos authentication by default - provos@cvs.openbsd.org 2000/08/02 11:27:05 [sshd.8 readconf.c auth-krb4.c] disallow kerberos authentication if we can't verify the TGT; from dugsong@ kerberos authentication is on by default only if you have a srvtab. - markus@cvs.openbsd.org 2000/08/04 14:30:07 [auth.c] unused - markus@cvs.openbsd.org 2000/08/04 14:30:35 [sshd_config] MaxStartups - markus@cvs.openbsd.org 2000/08/15 13:20:46 [authfd.c] cleanup; ok niels@ - markus@cvs.openbsd.org 2000/08/17 14:05:10 [session.c] cleanup login(1)-like jobs, no duplicate utmp entries - markus@cvs.openbsd.org 2000/08/17 14:06:34 [session.c sshd.8 sshd.c] sshd -u len, similar to telnetd --- sshd.8 | 65 ++++++++++++++++++++++++++++++++++++++++++++++++++--------------- 1 file changed, 50 insertions(+), 15 deletions(-) (limited to 'sshd.8') diff --git a/sshd.8 b/sshd.8 index b6aefe491..c8b99df38 100644 --- a/sshd.8 +++ b/sshd.8 @@ -9,7 +9,7 @@ .\" .\" Created: Sat Apr 22 21:55:14 1995 ylo .\" -.\" $Id: sshd.8,v 1.25 2000/07/11 07:31:39 djm Exp $ +.\" $Id: sshd.8,v 1.26 2000/08/18 03:59:06 djm Exp $ .\" .Dd September 25, 1999 .Dt SSHD 8 @@ -26,6 +26,7 @@ .Op Fl h Ar host_key_file .Op Fl k Ar key_gen_time .Op Fl p Ar port +.Op Fl u Ar len .Op Fl V Ar client_protocol_id .Sh DESCRIPTION .Nm @@ -104,7 +105,7 @@ into the machine). .Pp .Ss SSH protocol version 2 .Pp -Version 2 works similar: +Version 2 works similarly: Each host has a host-specific DSA key used to identify the host. However, when the daemon starts, it does not generate a server key. Forward security is provided through a Diffie-Hellman key agreement. @@ -211,6 +212,22 @@ Quiet mode. Nothing is sent to the system log. Normally the beginning, authentication, and termination of each connection is logged. +.It Fl u Ar len +This option is used to specify the size of the field +in the +.Li utmp +structure that holds the remote host name. +If the resolved host name is longer than +.Ar len , +the dotted decimal value will be used instead. +This allows hosts with very long host names that +overflow this field to still be uniquely identified. +Specifying +.Fl u0 +indicates that only dotted decimal addresses +should be put into the +.Pa utmp +file. .It Fl Q Do not print an error message if RSA support is missing. .It Fl V Ar client_protocol_id @@ -257,7 +274,7 @@ and .Ql ? can be used as wildcards in the patterns. -Only group names are valid, a numerical group ID isn't recognized. +Only group names are valid; a numerical group ID isn't recognized. By default login is allowed regardless of the primary group. .Pp .It Cm AllowUsers @@ -270,7 +287,7 @@ and .Ql ? can be used as wildcards in the patterns. -Only user names are valid, a numerical user ID isn't recognized. +Only user names are valid; a numerical user ID isn't recognized. By default login is allowed regardless of the user name. .Pp .It Cm Ciphers @@ -294,7 +311,7 @@ and .Ql ? can be used as wildcards in the patterns. -Only group names are valid, a numerical group ID isn't recognized. +Only group names are valid; a numerical group ID isn't recognized. By default login is allowed regardless of the primary group. .Pp .It Cm DenyUsers @@ -305,7 +322,7 @@ Login is disallowed for user names that match one of the patterns. and .Ql ? can be used as wildcards in the patterns. -Only user names are valid, a numerical user ID isn't recognized. +Only user names are valid; a numerical user ID isn't recognized. By default login is allowed regardless of the user name. .It Cm DSAAuthentication Specifies whether DSA authentication is allowed. @@ -321,7 +338,7 @@ or .Dq no . The default is .Dq no . -.It Cm HostDsaKey +.It Cm HostDSAKey Specifies the file containing the private DSA host key (default .Pa /etc/ssh_host_dsa_key ) used by SSH protocol 2.0. @@ -383,7 +400,8 @@ Specifies whether Kerberos authentication is allowed. This can be in the form of a Kerberos ticket, or if .Cm PasswordAuthentication is yes, the password provided by the user will be validated through -the Kerberos KDC. +the Kerberos KDC. To use this option, the server needs a +Kerberos servtab which allows the verification of the KDC's identity. Default is .Dq yes . .It Cm KerberosOrLocalPasswd @@ -443,11 +461,28 @@ Additional connections will be dropped until authentication succeeds or the .Cm LoginGraceTime expires for a connection. The default is 10. +.Pp +Alternatively, random early drop can be enabled by specifying +the three colon separated values +.Dq start:rate:full +(e.g. "10:30:60"). +.Nm +will refuse connection attempts with a probabillity of +.Dq rate/100 +(30%) +if there are currently +.Dq start +(10) +unauthenticated connections. +The probabillity increases linearly and all connection attempts +are refused if the number of unauthenticated connections reaches +.Dq full +(60). .It Cm PasswordAuthentication Specifies whether password authentication is allowed. The default is .Dq yes . -Note that this option applies to both protocol version 1 and 2. +Note that this option applies to both protocol versions 1 and 2. .It Cm PermitEmptyPasswords When password authentication is allowed, it specifies whether the server allows login to accounts with empty password strings. @@ -568,7 +603,7 @@ Specifies whether is used for interactive login sessions. Note that .Xr login 1 -is not never for remote command execution. +is never used for remote command execution. The default is .Dq no . .It Cm X11DisplayOffset @@ -666,7 +701,7 @@ You don't want to type them in; instead, copy the .Pa identity.pub file and edit it. .Pp -The options (if present) consists of comma-separated option +The options (if present) consist of comma-separated option specifications. No spaces are permitted, except within double quotes. The following option specifications are supported: @@ -740,7 +775,7 @@ and files contain host public keys for all known hosts. The global file should be prepared by the administrator (optional), and the per-user file is -maintained automatically: whenever the user connects an unknown host +maintained automatically: whenever the user connects from an unknown host its key is added to the per-user file. .Pp Each line in these files contains the following fields: hostnames, @@ -815,7 +850,7 @@ Contains the process ID of the listening for connections (if there are several daemons running concurrently for different ports, this contains the pid of the one started last). -The contents of this file are not sensitive; it can be world-readable. +The content of this file is not sensitive; it can be world-readable. .It Pa $HOME/.ssh/authorized_keys Lists the RSA keys that can be used to log into the user's account. This file must be readable by root (which may on some machines imply @@ -843,7 +878,7 @@ These files are consulted when using rhosts with RSA host authentication to check the public key of the host. The key must be listed in one of these files to be accepted. The client uses the same files -to verify that the remote host is the one we intended to connect. +to verify that the remote host is the one it intended to connect. These files should be writable only by root/the owner. .Pa /etc/ssh_known_hosts should be world-readable, and @@ -882,7 +917,7 @@ this file is exactly the same as for .Pa .rhosts . However, this file is not used by rlogin and rshd, so using this permits access using SSH only. -.Pa /etc/hosts.equiv +.It Pa /etc/hosts.equiv This file is used during .Pa .rhosts authentication. -- cgit v1.2.3