1SSHD_CONFIG(5) BSD File Formats Manual SSHD_CONFIG(5)
2
4 sshd_config — OpenSSH daemon configuration file
5
7 sshd(8) reads configuration data from /etc/ssh/sshd_config (or the file
8 specified with -f on the command line). The file contains keyword-argu‐
9 ment pairs, one per line. For each keyword, the first obtained value
10 will be used. Lines starting with ‘#’ and empty lines are interpreted as
11 comments. Arguments may optionally be enclosed in double quotes (") in
12 order to represent arguments containing spaces.
13 The possible keywords and their meanings are as follows (note that key‐
15 words are case-insensitive and arguments are case-sensitive):
16 AcceptEnv
18 Specifies what environment variables sent by the client will be
19 copied into the session's environ(7). See SendEnv and SetEnv in
20 ssh_config(5) for how to configure the client. The TERM environ‐
21 ment variable is always accepted whenever the client requests a
22 pseudo-terminal as it is required by the protocol. Variables are
23 specified by name, which may contain the wildcard characters ‘*’
24 and ‘?’. Multiple environment variables may be separated by
25 whitespace or spread across multiple AcceptEnv directives. Be
26 warned that some environment variables could be used to bypass
27 restricted user environments. For this reason, care should be
28 taken in the use of this directive. The default is not to accept
29 any environment variables.
30 AddressFamily
32 Specifies which address family should be used by sshd(8). Valid
33 arguments are any (the default), inet (use IPv4 only), or inet6
34 (use IPv6 only).
35 AllowAgentForwarding
37 Specifies whether ssh-agent(1) forwarding is permitted. The de‐
38 fault is yes. Note that disabling agent forwarding does not im‐
39 prove security unless users are also denied shell access, as they
40 can always install their own forwarders.
41 AllowGroups
43 This keyword can be followed by a list of group name patterns,
44 separated by spaces. If specified, login is allowed only for
45 users whose primary group or supplementary group list matches one
46 of the patterns. Only group names are valid; a numerical group
47 ID is not recognized. By default, login is allowed for all
48 groups. The allow/deny groups directives are processed in the
49 following order: DenyGroups, AllowGroups.
50 See PATTERNS in ssh_config(5) for more information on patterns.
52 AllowStreamLocalForwarding
54 Specifies whether StreamLocal (Unix-domain socket) forwarding is
55 permitted. The available options are yes (the default) or all to
56 allow StreamLocal forwarding, no to prevent all StreamLocal for‐
57 warding, local to allow local (from the perspective of ssh(1))
58 forwarding only or remote to allow remote forwarding only. Note
59 that disabling StreamLocal forwarding does not improve security
60 unless users are also denied shell access, as they can always in‐
61 stall their own forwarders.
62 AllowTcpForwarding
64 Specifies whether TCP forwarding is permitted. The available op‐
65 tions are yes (the default) or all to allow TCP forwarding, no to
66 prevent all TCP forwarding, local to allow local (from the per‐
67 spective of ssh(1)) forwarding only or remote to allow remote
68 forwarding only. Note that disabling TCP forwarding does not im‐
69 prove security unless users are also denied shell access, as they
70 can always install their own forwarders.
71 AllowUsers
73 This keyword can be followed by a list of user name patterns,
74 separated by spaces. If specified, login is allowed only for
75 user names that match one of the patterns. Only user names are
76 valid; a numerical user ID is not recognized. By default, login
77 is allowed for all users. If the pattern takes the form
78 USER@HOST then USER and HOST are separately checked, restricting
79 logins to particular users from particular hosts. HOST criteria
80 may additionally contain addresses to match in CIDR ad‐
81 dress/masklen format. The allow/deny users directives are pro‐
82 cessed in the following order: DenyUsers, AllowUsers.
83 See PATTERNS in ssh_config(5) for more information on patterns.
85 AuthenticationMethods
87 Specifies the authentication methods that must be successfully
88 completed for a user to be granted access. This option must be
89 followed by one or more lists of comma-separated authentication
90 method names, or by the single string any to indicate the default
91 behaviour of accepting any single authentication method. If the
92 default is overridden, then successful authentication requires
93 completion of every method in at least one of these lists.
94 For example, "publickey,password publickey,keyboard-interactive"
96 would require the user to complete public key authentication,
97 followed by either password or keyboard interactive authentica‐
98 tion. Only methods that are next in one or more lists are of‐
99 fered at each stage, so for this example it would not be possible
100 to attempt password or keyboard-interactive authentication before
101 public key.
102 For keyboard interactive authentication it is also possible to
104 restrict authentication to a specific device by appending a colon
105 followed by the device identifier bsdauth or pam. depending on
106 the server configuration. For example,
107 "keyboard-interactive:bsdauth" would restrict keyboard interac‐
108 tive authentication to the bsdauth device.
109 If the publickey method is listed more than once, sshd(8) veri‐
111 fies that keys that have been used successfully are not reused
112 for subsequent authentications. For example,
113 "publickey,publickey" requires successful authentication using
114 two different public keys.
115 Note that each authentication method listed should also be ex‐
117 plicitly enabled in the configuration.
118 The available authentication methods are: "gssapi-with-mic",
120 "hostbased", "keyboard-interactive", "none" (used for access to
121 password-less accounts when PermitEmptyPasswords is enabled),
122 "password" and "publickey".
123 AuthorizedKeysCommand
125 Specifies a program to be used to look up the user's public keys.
126 The program must be owned by root, not writable by group or oth‐
127 ers and specified by an absolute path. Arguments to
128 AuthorizedKeysCommand accept the tokens described in the TOKENS
129 section. If no arguments are specified then the username of the
130 target user is used.
131 The program should produce on standard output zero or more lines
133 of authorized_keys output (see AUTHORIZED_KEYS in sshd(8)).
134 AuthorizedKeysCommand is tried after the usual AuthorizedKeysFile
135 files and will not be executed if a matching key is found there.
136 By default, no AuthorizedKeysCommand is run.
137 AuthorizedKeysCommandUser
139 Specifies the user under whose account the AuthorizedKeysCommand
140 is run. It is recommended to use a dedicated user that has no
141 other role on the host than running authorized keys commands. If
142 AuthorizedKeysCommand is specified but AuthorizedKeysCommandUser
143 is not, then sshd(8) will refuse to start.
144 AuthorizedKeysFile
146 Specifies the file that contains the public keys used for user
147 authentication. The format is described in the AUTHORIZED_KEYS
148 FILE FORMAT section of sshd(8). Arguments to AuthorizedKeysFile
149 accept the tokens described in the TOKENS section. After expan‐
150 sion, AuthorizedKeysFile is taken to be an absolute path or one
151 relative to the user's home directory. Multiple files may be
152 listed, separated by whitespace. Alternately this option may be
153 set to none to skip checking for user keys in files. The default
154 is ".ssh/authorized_keys .ssh/authorized_keys2".
155 AuthorizedPrincipalsCommand
157 Specifies a program to be used to generate the list of allowed
158 certificate principals as per AuthorizedPrincipalsFile. The pro‐
159 gram must be owned by root, not writable by group or others and
160 specified by an absolute path. Arguments to
161 AuthorizedPrincipalsCommand accept the tokens described in the
162 TOKENS section. If no arguments are specified then the username
163 of the target user is used.
164 The program should produce on standard output zero or more lines
166 of AuthorizedPrincipalsFile output. If either
167 AuthorizedPrincipalsCommand or AuthorizedPrincipalsFile is speci‐
168 fied, then certificates offered by the client for authentication
169 must contain a principal that is listed. By default, no
170 AuthorizedPrincipalsCommand is run.
171 AuthorizedPrincipalsCommandUser
173 Specifies the user under whose account the
174 AuthorizedPrincipalsCommand is run. It is recommended to use a
175 dedicated user that has no other role on the host than running
176 authorized principals commands. If AuthorizedPrincipalsCommand
177 is specified but AuthorizedPrincipalsCommandUser is not, then
178 sshd(8) will refuse to start.
179 AuthorizedPrincipalsFile
181 Specifies a file that lists principal names that are accepted for
182 certificate authentication. When using certificates signed by a
183 key listed in TrustedUserCAKeys, this file lists names, one of
184 which must appear in the certificate for it to be accepted for
185 authentication. Names are listed one per line preceded by key
186 options (as described in AUTHORIZED_KEYS FILE FORMAT in sshd(8)).
187 Empty lines and comments starting with ‘#’ are ignored.
188 Arguments to AuthorizedPrincipalsFile accept the tokens described
190 in the TOKENS section. After expansion, AuthorizedPrincipalsFile
191 is taken to be an absolute path or one relative to the user's
192 home directory. The default is none, i.e. not to use a princi‐
193 pals file – in this case, the username of the user must appear in
194 a certificate's principals list for it to be accepted.
195 Note that AuthorizedPrincipalsFile is only used when authentica‐
197 tion proceeds using a CA listed in TrustedUserCAKeys and is not
198 consulted for certification authorities trusted via
199 ~/.ssh/authorized_keys, though the principals= key option offers
200 a similar facility (see sshd(8) for details).
201 Banner The contents of the specified file are sent to the remote user
203 before authentication is allowed. If the argument is none then
204 no banner is displayed. By default, no banner is displayed.
205 CASignatureAlgorithms
207 The default is handled system-wide by crypto-policies(7). To see
208 the defaults and how to modify this default, see manual page
209 update-crypto-policies(8).
210 Specifies which algorithms are allowed for signing of certifi‐
212 cates by certificate authorities (CAs). Certificates signed us‐
213 ing other algorithms will not be accepted for public key or host-
214 based authentication.
215 ChallengeResponseAuthentication
217 Specifies whether challenge-response authentication is allowed
218 (e.g. via PAM or through authentication styles supported in
219 login.conf(5)) The default is yes.
220 ChrootDirectory
222 Specifies the pathname of a directory to chroot(2) to after au‐
223 thentication. At session startup sshd(8) checks that all compo‐
224 nents of the pathname are root-owned directories which are not
225 writable by any other user or group. After the chroot, sshd(8)
226 changes the working directory to the user's home directory. Ar‐
227 guments to ChrootDirectory accept the tokens described in the
228 TOKENS section.
229 The ChrootDirectory must contain the necessary files and directo‐
231 ries to support the user's session. For an interactive session
232 this requires at least a shell, typically sh(1), and basic /dev
233 nodes such as null(4), zero(4), stdin(4), stdout(4), stderr(4),
234 and tty(4) devices. For file transfer sessions using SFTP no ad‐
235 ditional configuration of the environment is necessary if the in-
236 process sftp-server is used, though sessions which use logging
237 may require /dev/log inside the chroot directory on some operat‐
238 ing systems (see sftp-server(8) for details).
239 For safety, it is very important that the directory hierarchy be
241 prevented from modification by other processes on the system (es‐
242 pecially those outside the jail). Misconfiguration can lead to
243 unsafe environments which sshd(8) cannot detect.
244 The default is none, indicating not to chroot(2).
246 Ciphers
248 The default is handled system-wide by crypto-policies(7). To see
249 the defaults and how to modify this default, see manual page
250 update-crypto-policies(8).
251 Specifies the ciphers allowed. Multiple ciphers must be comma-
253 separated. If the specified list begins with a ‘+’ character,
254 then the specified ciphers will be appended to the built-in
255 openssh default set instead of replacing them. If the specified
256 list begins with a ‘-’ character, then the specified ciphers (in‐
257 cluding wildcards) will be removed from the built-in openssh de‐
258 fault set instead of replacing them. If the specified list be‐
259 gins with a ‘^’ character, then the specified ciphers will be
260 placed at the head of the built-in openssh default set.
261 The supported ciphers are:
263 3des-cbc
265 aes128-cbc
266 aes192-cbc
267 aes256-cbc
268 aes128-ctr
269 aes192-ctr
270 aes256-ctr
271 aes128-gcm@openssh.com
272 aes256-gcm@openssh.com
273 chacha20-poly1305@openssh.com
274 The list of available ciphers may also be obtained using "ssh -Q
276 cipher".
277 ClientAliveCountMax
279 Sets the number of client alive messages which may be sent with‐
280 out sshd(8) receiving any messages back from the client. If this
281 threshold is reached while client alive messages are being sent,
282 sshd will disconnect the client, terminating the session. It is
283 important to note that the use of client alive messages is very
284 different from TCPKeepAlive. The client alive messages are sent
285 through the encrypted channel and therefore will not be spoofa‐
286 ble. The TCP keepalive option enabled by TCPKeepAlive is spoofa‐
287 ble. The client alive mechanism is valuable when the client or
288 server depend on knowing when a connection has become unrespon‐
289 sive.
290 The default value is 3. If ClientAliveInterval is set to 15, and
292 ClientAliveCountMax is left at the default, unresponsive SSH
293 clients will be disconnected after approximately 45 seconds.
294 Setting a zero ClientAliveCountMax disables connection termina‐
295 tion.
296 ClientAliveInterval
298 Sets a timeout interval in seconds after which if no data has
299 been received from the client, sshd(8) will send a message
300 through the encrypted channel to request a response from the
301 client. The default is 0, indicating that these messages will
302 not be sent to the client.
303 Compression
305 Specifies whether compression is enabled after the user has au‐
306 thenticated successfully. The argument must be yes, delayed (a
307 legacy synonym for yes) or no. The default is yes.
308 DenyGroups
310 This keyword can be followed by a list of group name patterns,
311 separated by spaces. Login is disallowed for users whose primary
312 group or supplementary group list matches one of the patterns.
313 Only group names are valid; a numerical group ID is not recog‐
314 nized. By default, login is allowed for all groups. The al‐
315 low/deny groups directives are processed in the following order:
316 DenyGroups, AllowGroups.
317 See PATTERNS in ssh_config(5) for more information on patterns.
319 DenyUsers
321 This keyword can be followed by a list of user name patterns,
322 separated by spaces. Login is disallowed for user names that
323 match one of the patterns. Only user names are valid; a numeri‐
324 cal user ID is not recognized. By default, login is allowed for
325 all users. If the pattern takes the form USER@HOST then USER and
326 HOST are separately checked, restricting logins to particular
327 users from particular hosts. HOST criteria may additionally con‐
328 tain addresses to match in CIDR address/masklen format. The al‐
329 low/deny users directives are processed in the following order:
330 DenyUsers, AllowUsers.
331 See PATTERNS in ssh_config(5) for more information on patterns.
333 DisableForwarding
335 Disables all forwarding features, including X11, ssh-agent(1),
336 TCP and StreamLocal. This option overrides all other forwarding-
337 related options and may simplify restricted configurations.
338 ExposeAuthInfo
340 Writes a temporary file containing a list of authentication meth‐
341 ods and public credentials (e.g. keys) used to authenticate the
342 user. The location of the file is exposed to the user session
343 through the SSH_USER_AUTH environment variable. The default is
344 no.
345 FingerprintHash
347 Specifies the hash algorithm used when logging key fingerprints.
348 Valid options are: md5 and sha256. The default is sha256.
349 ForceCommand
351 Forces the execution of the command specified by ForceCommand,
352 ignoring any command supplied by the client and ~/.ssh/rc if
353 present. The command is invoked by using the user's login shell
354 with the -c option. This applies to shell, command, or subsystem
355 execution. It is most useful inside a Match block. The command
356 originally supplied by the client is available in the
357 SSH_ORIGINAL_COMMAND environment variable. Specifying a command
358 of internal-sftp will force the use of an in-process SFTP server
359 that requires no support files when used with ChrootDirectory.
360 The default is none.
361 GatewayPorts
363 Specifies whether remote hosts are allowed to connect to ports
364 forwarded for the client. By default, sshd(8) binds remote port
365 forwardings to the loopback address. This prevents other remote
366 hosts from connecting to forwarded ports. GatewayPorts can be
367 used to specify that sshd should allow remote port forwardings to
368 bind to non-loopback addresses, thus allowing other hosts to con‐
369 nect. The argument may be no to force remote port forwardings to
370 be available to the local host only, yes to force remote port
371 forwardings to bind to the wildcard address, or clientspecified
372 to allow the client to select the address to which the forwarding
373 is bound. The default is no.
374 GSSAPIAuthentication
376 Specifies whether user authentication based on GSSAPI is allowed.
377 The default is no.
378 GSSAPICleanupCredentials
380 Specifies whether to automatically destroy the user's credentials
381 cache on logout. The default is yes.
382 GSSAPIEnablek5users
384 Specifies whether to look at .k5users file for GSSAPI authentica‐
385 tion access control. Further details are described in ksu(1).
386 The default is no.
387 GSSAPIKeyExchange
389 Specifies whether key exchange based on GSSAPI is allowed. GSSAPI
390 key exchange doesn't rely on ssh keys to verify host identity.
391 The default is no.
392 GSSAPIStrictAcceptorCheck
394 Determines whether to be strict about the identity of the GSSAPI
395 acceptor a client authenticates against. If set to yes then the
396 client must authenticate against the host service on the current
397 hostname. If set to no then the client may authenticate against
398 any service key stored in the machine's default store. This fa‐
399 cility is provided to assist with operation on multi homed ma‐
400 chines. The default is yes.
401 GSSAPIStoreCredentialsOnRekey
403 Controls whether the user's GSSAPI credentials should be updated
404 following a successful connection rekeying. This option can be
405 used to accepted renewed or updated credentials from a compatible
406 client. The default is “no”.
407 For this to work GSSAPIKeyExchange needs to be enabled in the
409 server and also used by the client.
410 GSSAPIKexAlgorithms
412 The default is handled system-wide by crypto-policies(7). To see
413 the defaults and how to modify this default, see manual page
414 update-crypto-policies(8).
415 The list of key exchange algorithms that are accepted by GSSAPI
417 key exchange. Possible values are
418 gss-gex-sha1-
420 gss-group1-sha1-
421 gss-group14-sha1-
422 gss-group14-sha256-
423 gss-group16-sha512-
424 gss-nistp256-sha256-
425 gss-curve25519-sha256-
426 This option only applies to connections using GSSAPI.
427 HostbasedAcceptedAlgorithms
429 Specifies the signature algorithms that will be accepted for
430 hostbased authentication as a list of comma-separated patterns.
431 Alternately if the specified list begins with a ‘+’ character,
432 then the specified signature algorithms will be appended to the
433 default set instead of replacing them. If the specified list be‐
434 gins with a ‘-’ character, then the specified signature algo‐
435 rithms (including wildcards) will be removed from the default set
436 instead of replacing them. If the specified list begins with a
437 ‘^’ character, then the specified signature algorithms will be
438 placed at the head of the default set. The default for this op‐
439 tion is:
440 ssh-ed25519-cert-v01@openssh.com,
442 ecdsa-sha2-nistp256-cert-v01@openssh.com,
443 ecdsa-sha2-nistp384-cert-v01@openssh.com,
444 ecdsa-sha2-nistp521-cert-v01@openssh.com,
445 sk-ssh-ed25519-cert-v01@openssh.com,
446 sk-ecdsa-sha2-nistp256-cert-v01@openssh.com,
447 rsa-sha2-512-cert-v01@openssh.com,
448 rsa-sha2-256-cert-v01@openssh.com,
449 ssh-rsa-cert-v01@openssh.com,
450 ssh-ed25519,
451 ecdsa-sha2-nistp256,ecdsa-sha2-nistp384,ecdsa-sha2-nistp521,
452 sk-ssh-ed25519@openssh.com,
453 sk-ecdsa-sha2-nistp256@openssh.com,
454 rsa-sha2-512,rsa-sha2-256,ssh-rsa
455 The list of available signature algorithms may also be obtained
457 using "ssh -Q HostbasedAcceptedAlgorithms". This was formerly
458 named HostbasedAcceptedKeyTypes.
459 HostbasedAuthentication
461 Specifies whether rhosts or /etc/hosts.equiv authentication to‐
462 gether with successful public key client host authentication is
463 allowed (host-based authentication). The default is no.
464 HostbasedUsesNameFromPacketOnly
466 Specifies whether or not the server will attempt to perform a re‐
467 verse name lookup when matching the name in the ~/.shosts,
468 ~/.rhosts, and /etc/hosts.equiv files during
469 HostbasedAuthentication. A setting of yes means that sshd(8)
470 uses the name supplied by the client rather than attempting to
471 resolve the name from the TCP connection itself. The default is
472 no.
473 HostCertificate
475 Specifies a file containing a public host certificate. The cer‐
476 tificate's public key must match a private host key already spec‐
477 ified by HostKey. The default behaviour of sshd(8) is not to
478 load any certificates.
479 HostKey
481 Specifies a file containing a private host key used by SSH. The
482 defaults are /etc/ssh/ssh_host_ecdsa_key,
483 /etc/ssh/ssh_host_ed25519_key and /etc/ssh/ssh_host_rsa_key.
484 Note that sshd(8) will refuse to use a file if it is group/world-
486 accessible and that the HostKeyAlgorithms option restricts which
487 of the keys are actually used by sshd(8).
488 It is possible to have multiple host key files. It is also pos‐
490 sible to specify public host key files instead. In this case op‐
491 erations on the private key will be delegated to an ssh-agent(1).
492 HostKeyAgent
494 Identifies the UNIX-domain socket used to communicate with an
495 agent that has access to the private host keys. If the string
496 "SSH_AUTH_SOCK" is specified, the location of the socket will be
497 read from the SSH_AUTH_SOCK environment variable.
498 HostKeyAlgorithms
500 The default is handled system-wide by crypto-policies(7). To see
501 the defaults and how to modify this default, see manual page
502 update-crypto-policies(8).
503 Specifies the host key signature algorithms that the server of‐
505 fers. The list of available signature algorithms may also be ob‐
506 tained using "ssh -Q HostKeyAlgorithms".
507 IgnoreRhosts
509 Specifies whether to ignore per-user .rhosts and .shosts files
510 during HostbasedAuthentication. The system-wide /etc/hosts.equiv
511 and /etc/ssh/shosts.equiv are still used regardless of this set‐
512 ting.
513 Accepted values are yes (the default) to ignore all per-user
515 files, shosts-only to allow the use of .shosts but to ignore
516 .rhosts or no to allow both .shosts and rhosts.
517 IgnoreUserKnownHosts
519 Specifies whether sshd(8) should ignore the user's
520 ~/.ssh/known_hosts during HostbasedAuthentication and use only
521 the system-wide known hosts file /etc/ssh/known_hosts. The de‐
522 fault is “no”.
523 Include
525 Include the specified configuration file(s). Multiple pathnames
526 may be specified and each pathname may contain glob(7) wildcards
527 that will be expanded and processed in lexical order. Files
528 without absolute paths are assumed to be in /etc/ssh. An Include
529 directive may appear inside a Match block to perform conditional
530 inclusion.
531 IPQoS Specifies the IPv4 type-of-service or DSCP class for the connec‐
533 tion. Accepted values are af11, af12, af13, af21, af22, af23,
534 af31, af32, af33, af41, af42, af43, cs0, cs1, cs2, cs3, cs4, cs5,
535 cs6, cs7, ef, le, lowdelay, throughput, reliability, a numeric
536 value, or none to use the operating system default. This option
537 may take one or two arguments, separated by whitespace. If one
538 argument is specified, it is used as the packet class uncondi‐
539 tionally. If two values are specified, the first is automati‐
540 cally selected for interactive sessions and the second for non-
541 interactive sessions. The default is af21 (Low-Latency Data) for
542 interactive sessions and cs1 (Lower Effort) for non-interactive
543 sessions.
544 KbdInteractiveAuthentication
546 Specifies whether to allow keyboard-interactive authentication.
547 The argument to this keyword must be yes or no. The default is
548 to use whatever value ChallengeResponseAuthentication is set to
549 (by default yes).
550 KerberosAuthentication
552 Specifies whether the password provided by the user for
553 PasswordAuthentication will be validated through the Kerberos
554 KDC. To use this option, the server needs a Kerberos servtab
555 which allows the verification of the KDC's identity. The default
556 is no.
557 KerberosGetAFSToken
559 If AFS is active and the user has a Kerberos 5 TGT, attempt to
560 acquire an AFS token before accessing the user's home directory.
561 The default is no.
562 KerberosOrLocalPasswd
564 If password authentication through Kerberos fails then the pass‐
565 word will be validated via any additional local mechanism such as
566 /etc/passwd. The default is yes.
567 KerberosTicketCleanup
569 Specifies whether to automatically destroy the user's ticket
570 cache file on logout. The default is yes.
571 KerberosUniqueCCache
573 Specifies whether to store the acquired tickets in the per-ses‐
574 sion credential cache under /tmp/ or whether to use per-user cre‐
575 dential cache as configured in /etc/krb5.conf. The default value
576 no can lead to overwriting previous tickets by subseqent connec‐
577 tions to the same user account.
578 KerberosUseKuserok
580 Specifies whether to look at .k5login file for user's aliases.
581 The default is yes.
582 KexAlgorithms
584 The default is handled system-wide by crypto-policies(7). To see
585 the defaults and how to modify this default, see manual page
586 update-crypto-policies(8).
587 Specifies the available KEX (Key Exchange) algorithms. Multiple
589 algorithms must be comma-separated. Alternately if the specified
590 list begins with a ‘+’ character, then the specified methods will
591 be appended to the built-in openssh default set instead of re‐
592 placing them. If the specified list begins with a ‘-’ character,
593 then the specified methods (including wildcards) will be removed
594 from the built-in openssh default set instead of replacing them.
595 If the specified list begins with a ‘^’ character, then the spec‐
596 ified methods will be placed at the head of the built-in openssh
597 default set. The supported algorithms are:
598 curve25519-sha256
600 curve25519-sha256@libssh.org
601 diffie-hellman-group1-sha1
602 diffie-hellman-group14-sha1
603 diffie-hellman-group14-sha256
604 diffie-hellman-group16-sha512
605 diffie-hellman-group18-sha512
606 diffie-hellman-group-exchange-sha1
607 diffie-hellman-group-exchange-sha256
608 ecdh-sha2-nistp256
609 ecdh-sha2-nistp384
610 ecdh-sha2-nistp521
611 sntrup761x25519-sha512@openssh.com
612 The list of available key exchange algorithms may also be ob‐
614 tained using "ssh -Q KexAlgorithms".
615 ListenAddress
617 Specifies the local addresses sshd(8) should listen on. The fol‐
618 lowing forms may be used:
619 ListenAddress hostname|address [rdomain domain]
621 ListenAddress hostname:port [rdomain domain]
622 ListenAddress IPv4_address:port [rdomain domain]
623 ListenAddress [hostname|address]:port [rdomain domain]
624 The optional rdomain qualifier requests sshd(8) listen in an ex‐
626 plicit routing domain. If port is not specified, sshd will lis‐
627 ten on the address and all Port options specified. The default
628 is to listen on all local addresses on the current default rout‐
629 ing domain. Multiple ListenAddress options are permitted. For
630 more information on routing domains, see rdomain(4).
631 LoginGraceTime
633 The server disconnects after this time if the user has not suc‐
634 cessfully logged in. If the value is 0, there is no time limit.
635 The default is 120 seconds.
636 LogLevel
638 Gives the verbosity level that is used when logging messages from
639 sshd(8). The possible values are: QUIET, FATAL, ERROR, INFO,
640 VERBOSE, DEBUG, DEBUG1, DEBUG2, and DEBUG3. The default is INFO.
641 DEBUG and DEBUG1 are equivalent. DEBUG2 and DEBUG3 each specify
642 higher levels of debugging output. Logging with a DEBUG level
643 violates the privacy of users and is not recommended.
644 LogVerbose
646 Specify one or more overrides to LogLevel. An override consists
647 of a pattern lists that matches the source file, function and
648 line number to force detailed logging for. For example, an over‐
649 ride pattern of:
650 kex.c:*:1000,*:kex_exchange_identification():*,packet.c:*
652 would enable detailed logging for line 1000 of kex.c, everything
654 in the kex_exchange_identification() function, and all code in
655 the packet.c file. This option is intended for debugging and no
656 overrides are enabled by default.
657 MACs The default is handled system-wide by crypto-policies(7). To see
659 the defaults and how to modify this default, see manual page
660 update-crypto-policies(8).
661 Specifies the available MAC (message authentication code) algo‐
663 rithms. The MAC algorithm is used for data integrity protection.
664 Multiple algorithms must be comma-separated. If the specified
665 list begins with a ‘+’ character, then the specified algorithms
666 will be appended to the built-in openssh default set instead of
667 replacing them. If the specified list begins with a ‘-’ charac‐
668 ter, then the specified algorithms (including wildcards) will be
669 removed from the built-in openssh default set instead of replac‐
670 ing them. If the specified list begins with a ‘^’ character,
671 then the specified algorithms will be placed at the head of the
672 built-in openssh default set.
673 The algorithms that contain "-etm" calculate the MAC after en‐
675 cryption (encrypt-then-mac). These are considered safer and
676 their use recommended. The supported MACs are:
677 hmac-md5
679 hmac-md5-96
680 hmac-sha1
681 hmac-sha1-96
682 hmac-sha2-256
683 hmac-sha2-512
684 umac-64@openssh.com
685 umac-128@openssh.com
686 hmac-md5-etm@openssh.com
687 hmac-md5-96-etm@openssh.com
688 hmac-sha1-etm@openssh.com
689 hmac-sha1-96-etm@openssh.com
690 hmac-sha2-256-etm@openssh.com
691 hmac-sha2-512-etm@openssh.com
692 umac-64-etm@openssh.com
693 umac-128-etm@openssh.com
694 The list of available MAC algorithms may also be obtained using
696 "ssh -Q mac".
697 Match Introduces a conditional block. If all of the criteria on the
699 Match line are satisfied, the keywords on the following lines
700 override those set in the global section of the config file, un‐
701 til either another Match line or the end of the file. If a key‐
702 word appears in multiple Match blocks that are satisfied, only
703 the first instance of the keyword is applied.
704 The arguments to Match are one or more criteria-pattern pairs or
706 the single token All which matches all criteria. The available
707 criteria are User, Group, Host, LocalAddress, LocalPort, RDomain,
708 and Address (with RDomain representing the rdomain(4) on which
709 the connection was received).
710 The match patterns may consist of single entries or comma-sepa‐
712 rated lists and may use the wildcard and negation operators de‐
713 scribed in the PATTERNS section of ssh_config(5).
714 The patterns in an Address criteria may additionally contain ad‐
716 dresses to match in CIDR address/masklen format, such as
717 192.0.2.0/24 or 2001:db8::/32. Note that the mask length pro‐
718 vided must be consistent with the address - it is an error to
719 specify a mask length that is too long for the address or one
720 with bits set in this host portion of the address. For example,
721 192.0.2.0/33 and 192.0.2.0/8, respectively.
722 Only a subset of keywords may be used on the lines following a
724 Match keyword. Available keywords are AcceptEnv,
725 AllowAgentForwarding, AllowGroups, AllowStreamLocalForwarding,
726 AllowTcpForwarding, AllowUsers, AuthenticationMethods,
727 AuthorizedKeysCommand, AuthorizedKeysCommandUser,
728 AuthorizedKeysFile, AuthorizedPrincipalsCommand,
729 AuthorizedPrincipalsCommandUser, AuthorizedPrincipalsFile,
730 Banner, ChrootDirectory, ClientAliveCountMax,
731 ClientAliveInterval, DenyGroups, DenyUsers, DisableForwarding,
732 ForceCommand, GatewayPorts, GSSAPIAuthentication,
733 HostbasedAcceptedAlgorithms, HostbasedAuthentication,
734 HostbasedUsesNameFromPacketOnly, IgnoreRhosts, Include, IPQoS,
735 KbdInteractiveAuthentication, KerberosAuthentication,
736 KerberosUseKuserok, LogLevel, MaxAuthTries, MaxSessions,
737 PasswordAuthentication, PermitEmptyPasswords, PermitListen,
738 PermitOpen, PermitRootLogin, PermitTTY, PermitTunnel,
739 PermitUserRC, PubkeyAcceptedAlgorithms, PubkeyAuthentication,
740 RekeyLimit, RevokedKeys, RDomain, SetEnv, StreamLocalBindMask,
741 StreamLocalBindUnlink, TrustedUserCAKeys, X11DisplayOffset,
742 X11MaxDisplays, X11Forwarding and X11UseLocalhost.
743 MaxAuthTries
745 Specifies the maximum number of authentication attempts permitted
746 per connection. Once the number of failures reaches half this
747 value, additional failures are logged. The default is 6.
748 MaxSessions
750 Specifies the maximum number of open shell, login or subsystem
751 (e.g. sftp) sessions permitted per network connection. Multiple
752 sessions may be established by clients that support connection
753 multiplexing. Setting MaxSessions to 1 will effectively disable
754 session multiplexing, whereas setting it to 0 will prevent all
755 shell, login and subsystem sessions while still permitting for‐
756 warding. The default is 10.
757 MaxStartups
759 Specifies the maximum number of concurrent unauthenticated con‐
760 nections to the SSH daemon. Additional connections will be
761 dropped until authentication succeeds or the LoginGraceTime ex‐
762 pires for a connection. The default is 10:30:100.
763 Alternatively, random early drop can be enabled by specifying the
765 three colon separated values start:rate:full (e.g. "10:30:60").
766 sshd(8) will refuse connection attempts with a probability of
767 rate/100 (30%) if there are currently start (10) unauthenticated
768 connections. The probability increases linearly and all connec‐
769 tion attempts are refused if the number of unauthenticated con‐
770 nections reaches full (60).
771 ModuliFile
773 Specifies the moduli(5) file that contains the Diffie-Hellman
774 groups used for the “diffie-hellman-group-exchange-sha1” and
775 “diffie-hellman-group-exchange-sha256” key exchange methods. The
776 default is /etc/ssh/moduli.
777 PasswordAuthentication
779 Specifies whether password authentication is allowed. The de‐
780 fault is yes.
781 PermitEmptyPasswords
783 When password authentication is allowed, it specifies whether the
784 server allows login to accounts with empty password strings. The
785 default is no.
786 PermitListen
788 Specifies the addresses/ports on which a remote TCP port forward‐
789 ing may listen. The listen specification must be one of the fol‐
790 lowing forms:
791 PermitListen port
793 PermitListen host:port
794 Multiple permissions may be specified by separating them with
796 whitespace. An argument of any can be used to remove all re‐
797 strictions and permit any listen requests. An argument of none
798 can be used to prohibit all listen requests. The host name may
799 contain wildcards as described in the PATTERNS section in
800 ssh_config(5). The wildcard ‘*’ can also be used in place of a
801 port number to allow all ports. By default all port forwarding
802 listen requests are permitted. Note that the GatewayPorts option
803 may further restrict which addresses may be listened on. Note
804 also that ssh(1) will request a listen host of “localhost” if no
805 listen host was specifically requested, and this name is treated
806 differently to explicit localhost addresses of “127.0.0.1” and
807 “::1”.
808 PermitOpen
810 Specifies the destinations to which TCP port forwarding is per‐
811 mitted. The forwarding specification must be one of the follow‐
812 ing forms:
813 PermitOpen host:port
815 PermitOpen IPv4_addr:port
816 PermitOpen [IPv6_addr]:port
817 Multiple forwards may be specified by separating them with white‐
819 space. An argument of any can be used to remove all restrictions
820 and permit any forwarding requests. An argument of none can be
821 used to prohibit all forwarding requests. The wildcard ‘*’ can
822 be used for host or port to allow all hosts or ports respec‐
823 tively. Otherwise, no pattern matching or address lookups are
824 performed on supplied names. By default all port forwarding re‐
825 quests are permitted.
826 PermitRootLogin
828 Specifies whether root can log in using ssh(1). The argument
829 must be yes, prohibit-password, forced-commands-only, or no. The
830 default is prohibit-password.
831 If this option is set to prohibit-password (or its deprecated
833 alias, without-password), password and keyboard-interactive au‐
834 thentication are disabled for root.
835 If this option is set to forced-commands-only, root login with
837 public key authentication will be allowed, but only if the
838 command option has been specified (which may be useful for taking
839 remote backups even if root login is normally not allowed). All
840 other authentication methods are disabled for root.
841 If this option is set to no, root is not allowed to log in.
843 PermitTTY
845 Specifies whether pty(4) allocation is permitted. The default is
846 yes.
847 PermitTunnel
849 Specifies whether tun(4) device forwarding is allowed. The argu‐
850 ment must be yes, point-to-point (layer 3), ethernet (layer 2),
851 or no. Specifying yes permits both point-to-point and ethernet.
852 The default is no.
853 Independent of this setting, the permissions of the selected
855 tun(4) device must allow access to the user.
856 PermitUserEnvironment
858 Specifies whether ~/.ssh/environment and environment= options in
859 ~/.ssh/authorized_keys are processed by sshd(8). Valid options
860 are yes, no or a pattern-list specifying which environment vari‐
861 able names to accept (for example "LANG,LC_*"). The default is
862 no. Enabling environment processing may enable users to bypass
863 access restrictions in some configurations using mechanisms such
864 as LD_PRELOAD.
865 PermitUserRC
867 Specifies whether any ~/.ssh/rc file is executed. The default is
868 yes.
869 PerSourceMaxStartups
871 Specifies the number of unauthenticated connections allowed from
872 a given source address, or “none” if there is no limit. This
873 limit is applied in addition to MaxStartups, whichever is lower.
874 The default is none.
875 PerSourceNetBlockSize
877 Specifies the number of bits of source address that are grouped
878 together for the purposes of applying PerSourceMaxStartups lim‐
879 its. Values for IPv4 and optionally IPv6 may be specified, sepa‐
880 rated by a colon. The default is 32:128, which means each ad‐
881 dress is considered individually.
882 PidFile
884 Specifies the file that contains the process ID of the SSH dae‐
885 mon, or none to not write one. The default is /var/run/sshd.pid.
886 Port Specifies the port number that sshd(8) listens on. The default
888 is 22. Multiple options of this type are permitted. See also
889 ListenAddress.
890 PrintLastLog
892 Specifies whether sshd(8) should print the date and time of the
893 last user login when a user logs in interactively. The default
894 is yes.
895 PrintMotd
897 Specifies whether sshd(8) should print /etc/motd when a user logs
898 in interactively. (On some systems it is also printed by the
899 shell, /etc/profile, or equivalent.) The default is yes.
900 PubkeyAcceptedAlgorithms
902 The default is handled system-wide by crypto-policies(7). To see
903 the defaults and how to modify this default, see manual page
904 update-crypto-policies(8).
905 Specifies the signature algorithms that will be accepted for pub‐
907 lic key authentication as a list of comma-separated patterns.
908 Alternately if the specified list begins with a ‘+’ character,
909 then the specified algorithms will be appended to the built-in
910 openssh default set instead of replacing them. If the specified
911 list begins with a ‘-’ character, then the specified algorithms
912 (including wildcards) will be removed from the built-in openssh
913 default set instead of replacing them. If the specified list be‐
914 gins with a ‘^’ character, then the specified algorithms will be
915 placed at the head of the built-in openssh default set.
916 The list of available signature algorithms may also be obtained
918 using "ssh -Q PubkeyAcceptedAlgorithms".
919 PubkeyAuthOptions
921 Sets one or more public key authentication options. The sup‐
922 ported keywords are: none (the default; indicating no additional
923 options are enabled), touch-required and verify-required.
924 The touch-required option causes public key authentication using
926 a FIDO authenticator algorithm (i.e. ecdsa-sk or ed25519-sk) to
927 always require the signature to attest that a physically present
928 user explicitly confirmed the authentication (usually by touching
929 the authenticator). By default, sshd(8) requires user presence
930 unless overridden with an authorized_keys option. The
931 touch-required flag disables this override.
932 The verify-required option requires a FIDO key signature attest
934 that the user was verified, e.g. via a PIN.
935 Neither the touch-required or verify-required options have any
937 effect for other, non-FIDO, public key types.
938 PubkeyAuthentication
940 Specifies whether public key authentication is allowed. The de‐
941 fault is yes.
942 RekeyLimit
944 Specifies the maximum amount of data that may be transmitted be‐
945 fore the session key is renegotiated, optionally followed by a
946 maximum amount of time that may pass before the session key is
947 renegotiated. The first argument is specified in bytes and may
948 have a suffix of ‘K’, ‘M’, or ‘G’ to indicate Kilobytes,
949 Megabytes, or Gigabytes, respectively. The default is between
950 ‘1G’ and ‘4G’, depending on the cipher. The optional second
951 value is specified in seconds and may use any of the units docu‐
952 mented in the TIME FORMATS section. The default value for
953 RekeyLimit is default none, which means that rekeying is per‐
954 formed after the cipher's default amount of data has been sent or
955 received and no time based rekeying is done.
956 RevokedKeys
958 Specifies revoked public keys file, or none to not use one. Keys
959 listed in this file will be refused for public key authentica‐
960 tion. Note that if this file is not readable, then public key
961 authentication will be refused for all users. Keys may be speci‐
962 fied as a text file, listing one public key per line, or as an
963 OpenSSH Key Revocation List (KRL) as generated by ssh-keygen(1).
964 For more information on KRLs, see the KEY REVOCATION LISTS sec‐
965 tion in ssh-keygen(1).
966 RDomain
968 Specifies an explicit routing domain that is applied after au‐
969 thentication has completed. The user session, as well and any
970 forwarded or listening IP sockets, will be bound to this
971 rdomain(4). If the routing domain is set to %D, then the domain
972 in which the incoming connection was received will be applied.
973 SecurityKeyProvider
975 Specifies a path to a library that will be used when loading FIDO
976 authenticator-hosted keys, overriding the default of using the
977 built-in USB HID support.
978 SetEnv Specifies one or more environment variables to set in child ses‐
980 sions started by sshd(8) as “NAME=VALUE”. The environment value
981 may be quoted (e.g. if it contains whitespace characters). Envi‐
982 ronment variables set by SetEnv override the default environment
983 and any variables specified by the user via AcceptEnv or
984 PermitUserEnvironment.
985 StreamLocalBindMask
987 Sets the octal file creation mode mask (umask) used when creating
988 a Unix-domain socket file for local or remote port forwarding.
989 This option is only used for port forwarding to a Unix-domain
990 socket file.
991 The default value is 0177, which creates a Unix-domain socket
993 file that is readable and writable only by the owner. Note that
994 not all operating systems honor the file mode on Unix-domain
995 socket files.
996 StreamLocalBindUnlink
998 Specifies whether to remove an existing Unix-domain socket file
999 for local or remote port forwarding before creating a new one.
1000 If the socket file already exists and StreamLocalBindUnlink is
1001 not enabled, sshd will be unable to forward the port to the Unix-
1002 domain socket file. This option is only used for port forwarding
1003 to a Unix-domain socket file.
1004 The argument must be yes or no. The default is no.
1006 StrictModes
1008 Specifies whether sshd(8) should check file modes and ownership
1009 of the user's files and home directory before accepting login.
1010 This is normally desirable because novices sometimes accidentally
1011 leave their directory or files world-writable. The default is
1012 yes. Note that this does not apply to ChrootDirectory, whose
1013 permissions and ownership are checked unconditionally.
1014 Subsystem
1016 Configures an external subsystem (e.g. file transfer daemon).
1017 Arguments should be a subsystem name and a command (with optional
1018 arguments) to execute upon subsystem request.
1019 The command sftp-server implements the SFTP file transfer subsys‐
1021 tem.
1022 Alternately the name internal-sftp implements an in-process SFTP
1024 server. This may simplify configurations using ChrootDirectory
1025 to force a different filesystem root on clients.
1026 By default no subsystems are defined.
1028 SyslogFacility
1030 Gives the facility code that is used when logging messages from
1031 sshd(8). The possible values are: DAEMON, USER, AUTH, AUTHPRIV,
1032 LOCAL0, LOCAL1, LOCAL2, LOCAL3, LOCAL4, LOCAL5, LOCAL6, LOCAL7.
1033 The default is AUTH.
1034 TCPKeepAlive
1036 Specifies whether the system should send TCP keepalive messages
1037 to the other side. If they are sent, death of the connection or
1038 crash of one of the machines will be properly noticed. However,
1039 this means that connections will die if the route is down tempo‐
1040 rarily, and some people find it annoying. On the other hand, if
1041 TCP keepalives are not sent, sessions may hang indefinitely on
1042 the server, leaving "ghost" users and consuming server resources.
1043 The default is yes (to send TCP keepalive messages), and the
1045 server will notice if the network goes down or the client host
1046 crashes. This avoids infinitely hanging sessions.
1047 To disable TCP keepalive messages, the value should be set to no.
1049 TrustedUserCAKeys
1051 Specifies a file containing public keys of certificate authori‐
1052 ties that are trusted to sign user certificates for authentica‐
1053 tion, or none to not use one. Keys are listed one per line;
1054 empty lines and comments starting with ‘#’ are allowed. If a
1055 certificate is presented for authentication and has its signing
1056 CA key listed in this file, then it may be used for authentica‐
1057 tion for any user listed in the certificate's principals list.
1058 Note that certificates that lack a list of principals will not be
1059 permitted for authentication using TrustedUserCAKeys. For more
1060 details on certificates, see the CERTIFICATES section in
1061 ssh-keygen(1).
1062 UseDNS Specifies whether sshd(8) should look up the remote host name,
1064 and to check that the resolved host name for the remote IP ad‐
1065 dress maps back to the very same IP address.
1066 If this option is set to no (the default) then only addresses and
1068 not host names may be used in ~/.ssh/authorized_keys from and
1069 sshd_config Match Host directives.
1070 UsePAM Enables the Pluggable Authentication Module interface. If set to
1072 yes this will enable PAM authentication using
1073 ChallengeResponseAuthentication and PasswordAuthentication in ad‐
1074 dition to PAM account and session module processing for all au‐
1075 thentication types.
1076 Because PAM challenge-response authentication usually serves an
1078 equivalent role to password authentication, you should disable
1079 either PasswordAuthentication or ChallengeResponseAuthentication.
1080 If UsePAM is enabled, you will not be able to run sshd(8) as a
1082 non-root user. The default is no.
1083 VersionAddendum
1085 Optionally specifies additional text to append to the SSH proto‐
1086 col banner sent by the server upon connection. The default is
1087 none.
1088 X11DisplayOffset
1090 Specifies the first display number available for sshd(8)'s X11
1091 forwarding. This prevents sshd from interfering with real X11
1092 servers. The default is 10.
1093 X11MaxDisplays
1095 Specifies the maximum number of displays available for sshd(8)'s
1096 X11 forwarding. This prevents sshd from exhausting local ports.
1097 The default is 1000.
1098 X11Forwarding
1100 Specifies whether X11 forwarding is permitted. The argument must
1101 be yes or no. The default is no.
1102 When X11 forwarding is enabled, there may be additional exposure
1104 to the server and to client displays if the sshd(8) proxy display
1105 is configured to listen on the wildcard address (see
1106 X11UseLocalhost), though this is not the default. Additionally,
1107 the authentication spoofing and authentication data verification
1108 and substitution occur on the client side. The security risk of
1109 using X11 forwarding is that the client's X11 display server may
1110 be exposed to attack when the SSH client requests forwarding (see
1111 the warnings for ForwardX11 in ssh_config(5)). A system adminis‐
1112 trator may have a stance in which they want to protect clients
1113 that may expose themselves to attack by unwittingly requesting
1114 X11 forwarding, which can warrant a no setting.
1115 Note that disabling X11 forwarding does not prevent users from
1117 forwarding X11 traffic, as users can always install their own
1118 forwarders.
1119 X11UseLocalhost
1121 Specifies whether sshd(8) should bind the X11 forwarding server
1122 to the loopback address or to the wildcard address. By default,
1123 sshd binds the forwarding server to the loopback address and sets
1124 the hostname part of the DISPLAY environment variable to
1125 localhost. This prevents remote hosts from connecting to the
1126 proxy display. However, some older X11 clients may not function
1127 with this configuration. X11UseLocalhost may be set to no to
1128 specify that the forwarding server should be bound to the wild‐
1129 card address. The argument must be yes or no. The default is
1130 yes.
1131 XAuthLocation
1133 Specifies the full pathname of the xauth(1) program, or none to
1134 not use one. The default is /usr/bin/xauth.
1135
1137 sshd(8) command-line arguments and configuration file options that spec‐
1138 ify time may be expressed using a sequence of the form: time[qualifier],
1139 where time is a positive integer value and qualifier is one of the fol‐
1140 lowing:
1141 ⟨none⟩ seconds
1143 s | S seconds
1144 m | M minutes
1145 h | H hours
1146 d | D days
1147 w | W weeks
1148 Each member of the sequence is added together to calculate the total time
1150 value.
1151 Time format examples:
1153 600 600 seconds (10 minutes)
1155 10m 10 minutes
1156 1h30m 1 hour 30 minutes (90 minutes)
1157
1159 Arguments to some keywords can make use of tokens, which are expanded at
1160 runtime:
1161 %% A literal ‘%’.
1163 %D The routing domain in which the incoming connection was re‐
1164 ceived.
1165 %F The fingerprint of the CA key.
1166 %f The fingerprint of the key or certificate.
1167 %h The home directory of the user.
1168 %i The key ID in the certificate.
1169 %K The base64-encoded CA key.
1170 %k The base64-encoded key or certificate for authentication.
1171 %s The serial number of the certificate.
1172 %T The type of the CA key.
1173 %t The key or certificate type.
1174 %U The numeric user ID of the target user.
1175 %u The username.
1176 AuthorizedKeysCommand accepts the tokens %%, %f, %h, %k, %t, %U, and %u.
1178 AuthorizedKeysFile accepts the tokens %%, %h, %U, and %u.
1180 AuthorizedPrincipalsCommand accepts the tokens %%, %F, %f, %h, %i, %K,
1182 %k, %s, %T, %t, %U, and %u.
1183 AuthorizedPrincipalsFile accepts the tokens %%, %h, %U, and %u.
1185 ChrootDirectory accepts the tokens %%, %h, %U, and %u.
1187 RoutingDomain accepts the token %D.
1189
1191 /etc/ssh/sshd_config
1192 Contains configuration data for sshd(8). This file should be
1193 writable by root only, but it is recommended (though not neces‐
1194 sary) that it be world-readable.
1195
1197 sftp-server(8), sshd(8)
1198
1200 OpenSSH is a derivative of the original and free ssh 1.2.12 release by
1201 Tatu Ylonen. Aaron Campbell, Bob Beck, Markus Friedl, Niels Provos, Theo
1202 de Raadt and Dug Song removed many bugs, re-added newer features and cre‐
1203 ated OpenSSH. Markus Friedl contributed the support for SSH protocol
1204 versions 1.5 and 2.0. Niels Provos and Markus Friedl contributed support
1205 for privilege separation.
1206BSD April 4, 2021 BSD