3 .\" Author: Tatu Ylonen <ylo@cs.hut.fi>
4 .\" Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
5 .\" All rights reserved
7 .\" As far as I am concerned, the code I have written for this software
8 .\" can be used freely for any purpose. Any derived versions of this
9 .\" software must be clearly marked as such, and if the derived work is
10 .\" incompatible with the protocol description in the RFC file, it must be
11 .\" called by a name other than "ssh" or "Secure Shell".
13 .\" Copyright (c) 1999,2000 Markus Friedl. All rights reserved.
14 .\" Copyright (c) 1999 Aaron Campbell. All rights reserved.
15 .\" Copyright (c) 1999 Theo de Raadt. All rights reserved.
17 .\" Redistribution and use in source and binary forms, with or without
18 .\" modification, are permitted provided that the following conditions
20 .\" 1. Redistributions of source code must retain the above copyright
21 .\" notice, this list of conditions and the following disclaimer.
22 .\" 2. Redistributions in binary form must reproduce the above copyright
23 .\" notice, this list of conditions and the following disclaimer in the
24 .\" documentation and/or other materials provided with the distribution.
26 .\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
27 .\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
28 .\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
29 .\" IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
30 .\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
31 .\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
32 .\" DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
33 .\" THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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.
37 .\" $OpenBSD: sshd.8,v 1.257 2010/08/04 05:37:01 djm Exp $
38 .Dd $Mdocdate: August 4 2010 $
43 .Nd OpenSSH SSH daemon
49 .Op Fl C Ar connection_spec
50 .Op Fl c Ar host_certificate_file
51 .Op Fl f Ar config_file
52 .Op Fl g Ar login_grace_time
53 .Op Fl h Ar host_key_file
54 .Op Fl k Ar key_gen_time
61 (OpenSSH Daemon) is the daemon program for
63 Together these programs replace
67 and provide secure encrypted communications between two untrusted hosts
68 over an insecure network.
71 listens for connections from clients.
72 It is normally started at boot from
75 daemon for each incoming connection.
76 The forked daemons handle
77 key exchange, encryption, authentication, command execution,
81 can be configured using command-line options or a configuration file
84 command-line options override values specified in the
87 rereads its configuration file when it receives a hangup signal,
89 by executing itself with the name and options it was started with, e.g.\&
92 The options are as follows:
97 to use IPv4 addresses only.
101 to use IPv6 addresses only.
103 Specifies the number of bits in the ephemeral protocol version 1
104 server key (default 1024).
105 .It Fl C Ar connection_spec
106 Specify the connection parameters to use for the
111 directives in the configuration file
112 that would apply to the specified user, host, and address will be set before
113 the configuration is written to standard output.
114 The connection parameters are supplied as keyword=value pairs.
120 All are required and may be supplied in any order, either with multiple
122 options or as a comma-separated list.
123 .It Fl c Ar host_certificate_file
124 Specifies a path to a certificate file to identify
127 The certificate file must match a host key file specified using the
131 configuration directive.
133 When this option is specified,
135 will not detach and does not become a daemon.
136 This allows easy monitoring of
140 The server sends verbose debug output to standard error,
141 and does not put itself in the background.
142 The server also will not fork and will only process one connection.
143 This option is only intended for debugging for the server.
146 options increase the debugging level.
149 When this option is specified,
151 will send the output to the standard error instead of the system log.
152 .It Fl f Ar config_file
153 Specifies the name of the configuration file.
155 .Pa /etc/ssh/sshd_config .
157 refuses to start if there is no configuration file.
158 .It Fl g Ar login_grace_time
159 Gives the grace time for clients to authenticate themselves (default
161 If the client fails to authenticate the user within
162 this many seconds, the server disconnects and exits.
163 A value of zero indicates no limit.
164 .It Fl h Ar host_key_file
165 Specifies a file from which a host key is read.
166 This option must be given if
168 is not run as root (as the normal
169 host key files are normally not readable by anyone but root).
171 .Pa /etc/ssh/ssh_host_key
172 for protocol version 1, and
173 .Pa /etc/ssh/ssh_host_rsa_key
175 .Pa /etc/ssh/ssh_host_dsa_key
176 for protocol version 2.
177 It is possible to have multiple host key files for
178 the different protocol versions and host key algorithms.
186 from inetd because it needs to generate the server key before it can
187 respond to the client, and this may take tens of seconds.
188 Clients would have to wait too long if the key was regenerated every time.
189 However, with small key sizes (e.g. 512) using
193 .It Fl k Ar key_gen_time
194 Specifies how often the ephemeral protocol version 1 server key is
195 regenerated (default 3600 seconds, or one hour).
196 The motivation for regenerating the key fairly
197 often is that the key is not stored anywhere, and after about an hour
198 it becomes impossible to recover the key for decrypting intercepted
199 communications even if the machine is cracked into or physically
201 A value of zero indicates that the key will never be regenerated.
203 Can be used to give options in the format used in the configuration file.
204 This is useful for specifying options for which there is no separate
206 For full details of the options, and their values, see
209 Specifies the port on which the server listens for connections
211 Multiple port options are permitted.
212 Ports specified in the configuration file with the
214 option are ignored when a command-line port is specified.
215 Ports specified using the
217 option override command-line ports.
220 Nothing is sent to the system log.
221 Normally the beginning,
222 authentication, and termination of each connection is logged.
225 Check the validity of the configuration file, output the effective configuration
226 to stdout and then exit.
229 rules may be applied by specifying the connection parameters using one or more
234 Only check the validity of the configuration file and sanity of the keys.
235 This is useful for updating
237 reliably as configuration options may change.
239 This option is used to specify the size of the field
242 structure that holds the remote host name.
243 If the resolved host name is longer than
245 the dotted decimal value will be used instead.
246 This allows hosts with very long host names that
247 overflow this field to still be uniquely identified.
250 indicates that only dotted decimal addresses
251 should be put into the
255 may also be used to prevent
257 from making DNS requests unless the authentication
258 mechanism or configuration requires it.
259 Authentication mechanisms that may require DNS include
260 .Cm RhostsRSAAuthentication ,
261 .Cm HostbasedAuthentication ,
263 .Cm from="pattern-list"
264 option in a key file.
265 Configuration options that require DNS include using a
272 The OpenSSH SSH daemon supports SSH protocols 1 and 2.
273 The default is to use protocol 2 only,
274 though this can be changed via the
278 Protocol 2 supports both RSA and DSA keys;
279 protocol 1 only supports RSA keys.
281 each host has a host-specific key,
283 used to identify the host.
285 Forward security for protocol 1 is provided through
286 an additional server key,
288 generated when the server starts.
289 This key is normally regenerated every hour if it has been used, and
290 is never stored on disk.
291 Whenever a client connects, the daemon responds with its public
292 host and server keys.
293 The client compares the
294 RSA host key against its own database to verify that it has not changed.
295 The client then generates a 256-bit random number.
297 random number using both the host key and the server key, and sends
298 the encrypted number to the server.
299 Both sides then use this
300 random number as a session key which is used to encrypt all further
301 communications in the session.
302 The rest of the session is encrypted
303 using a conventional cipher, currently Blowfish or 3DES, with 3DES
304 being used by default.
305 The client selects the encryption algorithm
306 to use from those offered by the server.
309 forward security is provided through a Diffie-Hellman key agreement.
310 This key agreement results in a shared session key.
311 The rest of the session is encrypted using a symmetric cipher, currently
312 128-bit AES, Blowfish, 3DES, CAST128, Arcfour, 192-bit AES, or 256-bit AES.
313 The client selects the encryption algorithm
314 to use from those offered by the server.
315 Additionally, session integrity is provided
316 through a cryptographic message authentication code
317 (hmac-md5, hmac-sha1, umac-64 or hmac-ripemd160).
319 Finally, the server and the client enter an authentication dialog.
320 The client tries to authenticate itself using
321 host-based authentication,
322 public key authentication,
323 challenge-response authentication,
324 or password authentication.
326 Regardless of the authentication type, the account is checked to
327 ensure that it is accessible. An account is not accessible if it is
330 or its group is listed in
332 \&. The definition of a locked account is system dependant. Some platforms
333 have their own account database (eg AIX) and some modify the passwd field (
335 on Solaris and UnixWare,
342 on FreeBSD and a leading
345 If there is a requirement to disable password authentication
346 for the account while allowing still public-key, then the passwd field
347 should be set to something other than these values (eg
353 If the client successfully authenticates itself, a dialog for
354 preparing the session is entered.
355 At this time the client may request
356 things like allocating a pseudo-tty, forwarding X11 connections,
357 forwarding TCP connections, or forwarding the authentication agent
358 connection over the secure channel.
360 After this, the client either requests a shell or execution of a command.
361 The sides then enter session mode.
362 In this mode, either side may send
363 data at any time, and such data is forwarded to/from the shell or
364 command on the server side, and the user terminal in the client side.
366 When the user program terminates and all forwarded X11 and other
367 connections have been closed, the server sends command exit status to
368 the client, and both sides exit.
370 When a user successfully logs in,
373 .Bl -enum -offset indent
375 If the login is on a tty, and no command has been specified,
376 prints last login time and
378 (unless prevented in the configuration file or by
384 If the login is on a tty, records login time.
388 .Pa /var/run/nologin ;
389 if one exists, it prints the contents and quits
392 Changes to run with normal user privileges.
394 Sets up basic environment.
397 .Pa ~/.ssh/environment ,
398 if it exists, and users are allowed to change their environment.
400 .Cm PermitUserEnvironment
404 Changes to user's home directory.
408 exists, runs it; else if
415 files are given the X11
416 authentication protocol and cookie (if applicable) in standard input.
421 Runs user's shell or command.
428 runs it after reading the
429 environment files but before starting the user's shell or command.
430 It must not produce any output on stdout; stderr must be used
432 If X11 forwarding is in use, it will receive the "proto cookie" pair in
433 its standard input (and
440 will not run xauth automatically to add X11 cookies.
442 The primary purpose of this file is to run any initialization routines
443 which may be needed before the user's home directory becomes
444 accessible; AFS is a particular example of such an environment.
446 This file will probably contain some initialization code followed by
447 something similar to:
448 .Bd -literal -offset 3n
449 if read proto cookie && [ -n "$DISPLAY" ]; then
450 if [ `echo $DISPLAY | cut -c1-10` = 'localhost:' ]; then
451 # X11UseLocalhost=yes
452 echo add unix:`echo $DISPLAY |
453 cut -c11-` $proto $cookie
456 echo add $DISPLAY $proto $cookie
461 If this file does not exist,
464 does not exist either, xauth is used to add the cookie.
465 .Sh AUTHORIZED_KEYS FILE FORMAT
466 .Cm AuthorizedKeysFile
467 specifies the file containing public keys for
468 public key authentication;
469 if none is specified, the default is
470 .Pa ~/.ssh/authorized_keys .
471 Each line of the file contains one
472 key (empty lines and lines starting with a
476 Protocol 1 public keys consist of the following space-separated fields:
477 options, bits, exponent, modulus, comment.
478 Protocol 2 public key consist of:
479 options, keytype, base64-encoded key, comment.
480 The options field is optional;
481 its presence is determined by whether the line starts
482 with a number or not (the options field never starts with a number).
483 The bits, exponent, modulus, and comment fields give the RSA key for
484 protocol version 1; the
485 comment field is not used for anything (but may be convenient for the
486 user to identify the key).
487 For protocol version 2 the keytype is
492 Note that lines in this file are usually several hundred bytes long
493 (because of the size of the public key encoding) up to a limit of
494 8 kilobytes, which permits DSA keys up to 8 kilobits and RSA
495 keys up to 16 kilobits.
496 You don't want to type them in; instead, copy the
504 enforces a minimum RSA key modulus size for protocol 1
505 and protocol 2 keys of 768 bits.
507 The options (if present) consist of comma-separated option
509 No spaces are permitted, except within double quotes.
510 The following option specifications are supported (note
511 that option keywords are case-insensitive):
513 .It Cm cert-authority
514 Specifies that the listed key is a certification authority (CA) that is
515 trusted to validate signed certificates for user authentication.
517 Certificates may encode access restrictions similar to these key options.
518 If both certificate restrictions and key options are present, the most
519 restrictive union of the two is applied.
520 .It Cm command="command"
521 Specifies that the command is executed whenever this key is used for
523 The command supplied by the user (if any) is ignored.
524 The command is run on a pty if the client requests a pty;
525 otherwise it is run without a tty.
526 If an 8-bit clean channel is required,
527 one must not request a pty or should specify
529 A quote may be included in the command by quoting it with a backslash.
530 This option might be useful
531 to restrict certain public keys to perform just a specific operation.
532 An example might be a key that permits remote backups but nothing else.
533 Note that the client may specify TCP and/or X11
534 forwarding unless they are explicitly prohibited.
535 The command originally supplied by the client is available in the
536 .Ev SSH_ORIGINAL_COMMAND
537 environment variable.
538 Note that this option applies to shell, command or subsystem execution.
539 Also note that this command may be superseded by either a
542 directive or a command embedded in a certificate.
543 .It Cm environment="NAME=value"
544 Specifies that the string is to be added to the environment when
545 logging in using this key.
546 Environment variables set this way
547 override other default environment values.
548 Multiple options of this type are permitted.
549 Environment processing is disabled by default and is
551 .Cm PermitUserEnvironment
553 This option is automatically disabled if
556 .It Cm from="pattern-list"
557 Specifies that in addition to public key authentication, either the canonical
558 name of the remote host or its IP address must be present in the
559 comma-separated list of patterns.
564 for more information on patterns.
566 In addition to the wildcard matching that may be applied to hostnames or
569 stanza may match IP addresses using CIDR address/masklen notation.
571 The purpose of this option is to optionally increase security: public key
572 authentication by itself does not trust the network or name servers or
573 anything (but the key); however, if somebody somehow steals the key, the key
574 permits an intruder to log in from anywhere in the world.
575 This additional option makes using a stolen key more difficult (name
576 servers and/or routers would have to be compromised in addition to
578 .It Cm no-agent-forwarding
579 Forbids authentication agent forwarding when this key is used for
581 .It Cm no-port-forwarding
582 Forbids TCP forwarding when this key is used for authentication.
583 Any port forward requests by the client will return an error.
584 This might be used, e.g. in connection with the
588 Prevents tty allocation (a request to allocate a pty will fail).
590 Disables execution of
592 .It Cm no-X11-forwarding
593 Forbids X11 forwarding when this key is used for authentication.
594 Any X11 forward requests by the client will return an error.
595 .It Cm permitopen="host:port"
598 port forwarding such that it may only connect to the specified host and
600 IPv6 addresses can be specified by enclosing the address in square brackets.
603 options may be applied separated by commas.
604 No pattern matching is performed on the specified hostnames,
605 they must be literal domains or addresses.
606 .It Cm principals="principals"
609 line, specifies allowed principals for certificate authentication as a
610 comma-separated list.
611 At least one name from the list must appear in the certificate's
612 list of principals for the certificate to be accepted.
613 This option is ignored for keys that are not marked as trusted certificate
620 device on the server.
621 Without this option, the next available device will be used if
622 the client requests a tunnel.
625 An example authorized_keys file:
626 .Bd -literal -offset 3n
627 # Comments allowed at start of line
628 ssh-rsa AAAAB3Nza...LiPk== user@example.net
629 from="*.sales.example.net,!pc.sales.example.net" ssh-rsa
630 AAAAB2...19Q== john@example.net
631 command="dump /home",no-pty,no-port-forwarding ssh-dss
632 AAAAC3...51R== example.net
633 permitopen="192.0.2.1:80",permitopen="192.0.2.2:25" ssh-dss
635 tunnel="0",command="sh /etc/netstart tun0" ssh-rsa AAAA...==
638 .Sh SSH_KNOWN_HOSTS FILE FORMAT
640 .Pa /etc/ssh/ssh_known_hosts
642 .Pa ~/.ssh/known_hosts
643 files contain host public keys for all known hosts.
644 The global file should
645 be prepared by the administrator (optional), and the per-user file is
646 maintained automatically: whenever the user connects from an unknown host,
647 its key is added to the per-user file.
649 Each line in these files contains the following fields: markers (optional),
650 hostnames, bits, exponent, modulus, comment.
651 The fields are separated by spaces.
653 The marker is optional, but if it is present then it must be one of
654 .Dq @cert-authority ,
655 to indicate that the line contains a certification authority (CA) key,
658 to indicate that the key contained on the line is revoked and must not ever
660 Only one marker should be used on a key line.
662 Hostnames is a comma-separated list of patterns
667 wildcards); each pattern in turn is matched against the canonical host
668 name (when authenticating a client) or against the user-supplied
669 name (when authenticating a server).
670 A pattern may also be preceded by
672 to indicate negation: if the host name matches a negated
673 pattern, it is not accepted (by that line) even if it matched another
675 A hostname or address may optionally be enclosed within
679 brackets then followed by
681 and a non-standard port number.
683 Alternately, hostnames may be stored in a hashed form which hides host names
684 and addresses should the file's contents be disclosed.
685 Hashed hostnames start with a
688 Only one hashed hostname may appear on a single line and none of the above
689 negation or wildcard operators may be applied.
691 Bits, exponent, and modulus are taken directly from the RSA host key; they
692 can be obtained, for example, from
693 .Pa /etc/ssh/ssh_host_key.pub .
694 The optional comment field continues to the end of the line, and is not used.
698 and empty lines are ignored as comments.
700 When performing host authentication, authentication is accepted if any
701 matching line has the proper key; either one that matches exactly or,
702 if the server has presented a certificate for authentication, the key
703 of the certification authority that signed the certificate.
704 For a key to be trusted as a certification authority, it must use the
706 marker described above.
708 The known hosts file also provides a facility to mark keys as revoked,
709 for example when it is known that the associated private key has been
711 Revoked keys are specified by including the
713 marker at the beginning of the key line, and are never accepted for
714 authentication or as certification authorities, but instead will
715 produce a warning from
717 when they are encountered.
719 It is permissible (but not
720 recommended) to have several lines or different host keys for the same
722 This will inevitably happen when short forms of host names
723 from different domains are put in the file.
725 that the files contain conflicting information; authentication is
726 accepted if valid information can be found from either file.
728 Note that the lines in these files are typically hundreds of characters
729 long, and you definitely don't want to type in the host keys by hand.
730 Rather, generate them by a script,
733 .Pa /etc/ssh/ssh_host_key.pub
734 and adding the host names at the front.
736 also offers some basic automated editing for
737 .Pa ~/.ssh/known_hosts
738 including removing hosts matching a host name and converting all host
739 names to their hashed representations.
741 An example ssh_known_hosts file:
742 .Bd -literal -offset 3n
743 # Comments allowed at start of line
744 closenet,...,192.0.2.53 1024 37 159...93 closenet.example.net
745 cvs.example.net,192.0.2.10 ssh-rsa AAAA1234.....=
747 |1|JfKTdBh7rNbXkVAQCRp4OQoPfmI=|USECr3SWf1JUPsms5AqfD5QfxkM= ssh-rsa
750 @revoked * ssh-rsa AAAAB5W...
751 # A CA key, accepted for any host in *.mydomain.com or *.mydomain.org
752 @cert-authority *.mydomain.org,*.mydomain.com ssh-rsa AAAAB5W...
755 .Bl -tag -width Ds -compact
757 This file is used to suppress printing the last login time and
765 It does not suppress printing of the banner specified by
769 This file is used for host-based authentication (see
771 for more information).
772 On some machines this file may need to be
773 world-readable if the user's home directory is on an NFS partition,
777 Additionally, this file must be owned by the user,
778 and must not have write permissions for anyone else.
780 permission for most machines is read/write for the user, and not
781 accessible by others.
784 This file is used in exactly the same way as
786 but allows host-based authentication without permitting login with
790 This directory is the default location for all user-specific configuration
791 and authentication information.
792 There is no general requirement to keep the entire contents of this directory
793 secret, but the recommended permissions are read/write/execute for the user,
794 and not accessible by others.
796 .It ~/.ssh/authorized_keys
797 Lists the public keys (RSA/DSA) that can be used for logging in as this user.
798 The format of this file is described above.
799 The content of the file is not highly sensitive, but the recommended
800 permissions are read/write for the user, and not accessible by others.
804 directory, or the user's home directory are writable
805 by other users, then the file could be modified or replaced by unauthorized
809 will not allow it to be used unless the
811 option has been set to
814 .It ~/.ssh/environment
815 This file is read into the environment at login (if it exists).
816 It can only contain empty lines, comment lines (that start with
818 and assignment lines of the form name=value.
819 The file should be writable
820 only by the user; it need not be readable by anyone else.
821 Environment processing is disabled by default and is
823 .Cm PermitUserEnvironment
826 .It ~/.ssh/known_hosts
827 Contains a list of host keys for all hosts the user has logged into
828 that are not already in the systemwide list of known host keys.
829 The format of this file is described above.
830 This file should be writable only by root/the owner and
831 can, but need not be, world-readable.
834 Contains initialization routines to be run before
835 the user's home directory becomes accessible.
836 This file should be writable only by the user, and need not be
837 readable by anyone else.
841 Access controls that should be enforced by tcp-wrappers are defined here.
842 Further details are described in
846 This file is for host-based authentication (see
848 It should only be writable by root.
851 Contains Diffie-Hellman groups used for the "Diffie-Hellman Group Exchange".
852 The file format is described in
862 refuses to let anyone except root log in.
863 The contents of the file
864 are displayed to anyone trying to log in, and non-root connections are
866 The file should be world-readable.
868 .It /etc/ssh/shosts.equiv
869 This file is used in exactly the same way as
871 but allows host-based authentication without permitting login with
874 .It /etc/ssh/ssh_host_key
875 .It /etc/ssh/ssh_host_dsa_key
876 .It /etc/ssh/ssh_host_rsa_key
877 These three files contain the private parts of the host keys.
878 These files should only be owned by root, readable only by root, and not
879 accessible to others.
882 does not start if these files are group/world-accessible.
884 .It /etc/ssh/ssh_host_key.pub
885 .It /etc/ssh/ssh_host_dsa_key.pub
886 .It /etc/ssh/ssh_host_rsa_key.pub
887 These three files contain the public parts of the host keys.
888 These files should be world-readable but writable only by
890 Their contents should match the respective private parts.
892 really used for anything; they are provided for the convenience of
893 the user so their contents can be copied to known hosts files.
894 These files are created using
897 .It /etc/ssh/ssh_known_hosts
898 Systemwide list of known host keys.
899 This file should be prepared by the
900 system administrator to contain the public host keys of all machines in the
902 The format of this file is described above.
903 This file should be writable only by root/the owner and
904 should be world-readable.
906 .It /etc/ssh/sshd_config
907 Contains configuration data for
909 The file format and configuration options are described in
915 it can be used to specify
916 machine-specific login-time initializations globally.
917 This file should be writable only by root, and should be world-readable.
923 during privilege separation in the pre-authentication phase.
924 The directory should not contain any files and must be owned by root
925 and not group or world-writable.
927 .It /var/run/sshd.pid
928 Contains the process ID of the
930 listening for connections (if there are several daemons running
931 concurrently for different ports, this contains the process ID of the one
933 The content of this file is not sensitive; it can be world-readable.
951 OpenSSH is a derivative of the original and free
952 ssh 1.2.12 release by Tatu Ylonen.
953 Aaron Campbell, Bob Beck, Markus Friedl, Niels Provos,
954 Theo de Raadt and Dug Song
955 removed many bugs, re-added newer features and
957 Markus Friedl contributed the support for SSH
958 protocol versions 1.5 and 2.0.
959 Niels Provos and Markus Friedl contributed support
960 for privilege separation.
962 System security is not improved unless
967 are disabled (thus completely disabling