diff options
Diffstat (limited to 'crypto/openssh/sshd_config.0')
| -rw-r--r-- | crypto/openssh/sshd_config.0 | 360 |
1 files changed, 200 insertions, 160 deletions
diff --git a/crypto/openssh/sshd_config.0 b/crypto/openssh/sshd_config.0 index 1c82d44..be48e13 100644 --- a/crypto/openssh/sshd_config.0 +++ b/crypto/openssh/sshd_config.0 @@ -1,7 +1,7 @@ SSHD_CONFIG(5) File Formats Manual SSHD_CONFIG(5) NAME - sshd_config - OpenSSH SSH daemon configuration file + sshd_config M-bM-^@M-^S OpenSSH SSH daemon configuration file SYNOPSIS /etc/ssh/sshd_config @@ -9,7 +9,7 @@ SYNOPSIS DESCRIPTION sshd(8) reads configuration data from /etc/ssh/sshd_config (or the file specified with -f on the command line). The file contains keyword- - argument pairs, one per line. Lines starting with `#' and empty lines + argument pairs, one per line. Lines starting with M-bM-^@M-^X#M-bM-^@M-^Y and empty lines are interpreted as comments. Arguments may optionally be enclosed in double quotes (") in order to represent arguments containing spaces. @@ -22,7 +22,7 @@ DESCRIPTION ssh_config(5) for how to configure the client. Note that environment passing is only supported for protocol 2. Variables are specified by name, which may contain the wildcard characters - `*' and `?'. Multiple environment variables may be separated by + M-bM-^@M-^X*M-bM-^@M-^Y and M-bM-^@M-^X?M-bM-^@M-^Y. Multiple environment variables may be separated by whitespace or spread across multiple AcceptEnv directives. Be warned that some environment variables could be used to bypass restricted user environments. For this reason, care should be @@ -31,14 +31,14 @@ DESCRIPTION AddressFamily Specifies which address family should be used by sshd(8). Valid - arguments are ``any'', ``inet'' (use IPv4 only), or ``inet6'' - (use IPv6 only). The default is ``any''. + arguments are M-bM-^@M-^\anyM-bM-^@M-^], M-bM-^@M-^\inetM-bM-^@M-^] (use IPv4 only), or M-bM-^@M-^\inet6M-bM-^@M-^] (use IPv6 + only). The default is M-bM-^@M-^\anyM-bM-^@M-^]. AllowAgentForwarding Specifies whether ssh-agent(1) forwarding is permitted. The - default is ``yes''. Note that disabling agent forwarding does - not improve security unless users are also denied shell access, - as they can always install their own forwarders. + default is M-bM-^@M-^\yesM-bM-^@M-^]. Note that disabling agent forwarding does not + improve security unless users are also denied shell access, as + they can always install their own forwarders. AllowGroups This keyword can be followed by a list of group name patterns, @@ -54,21 +54,21 @@ DESCRIPTION AllowTcpForwarding Specifies whether TCP forwarding is permitted. The available - options are ``yes'' or ``all'' to allow TCP forwarding, ``no'' to - prevent all TCP forwarding, ``local'' to allow local (from the - perspective of ssh(1)) forwarding only or ``remote'' to allow - remote forwarding only. The default is ``yes''. Note that + options are M-bM-^@M-^\yesM-bM-^@M-^] or M-bM-^@M-^\allM-bM-^@M-^] to allow TCP forwarding, M-bM-^@M-^\noM-bM-^@M-^] to + prevent all TCP forwarding, M-bM-^@M-^\localM-bM-^@M-^] to allow local (from the + perspective of ssh(1)) forwarding only or M-bM-^@M-^\remoteM-bM-^@M-^] to allow + remote forwarding only. The default is M-bM-^@M-^\yesM-bM-^@M-^]. Note that disabling TCP forwarding does not improve security unless users are also denied shell access, as they can always install their own forwarders. AllowStreamLocalForwarding Specifies whether StreamLocal (Unix-domain socket) forwarding is - permitted. The available options are ``yes'' or ``all'' to allow - StreamLocal forwarding, ``no'' to prevent all StreamLocal - forwarding, ``local'' to allow local (from the perspective of - ssh(1)) forwarding only or ``remote'' to allow remote forwarding - only. The default is ``yes''. Note that disabling StreamLocal + permitted. The available options are M-bM-^@M-^\yesM-bM-^@M-^] or M-bM-^@M-^\allM-bM-^@M-^] to allow + StreamLocal forwarding, M-bM-^@M-^\noM-bM-^@M-^] to prevent all StreamLocal + forwarding, M-bM-^@M-^\localM-bM-^@M-^] to allow local (from the perspective of + ssh(1)) forwarding only or M-bM-^@M-^\remoteM-bM-^@M-^] to allow remote forwarding + only. The default is M-bM-^@M-^\yesM-bM-^@M-^]. Note that disabling StreamLocal forwarding does not improve security unless users are also denied shell access, as they can always install their own forwarders. @@ -92,8 +92,8 @@ DESCRIPTION method names. Successful authentication requires completion of every method in at least one of these lists. - For example, an argument of ``publickey,password - publickey,keyboard-interactive'' would require the user to + For example, an argument of M-bM-^@M-^\publickey,password + publickey,keyboard-interactiveM-bM-^@M-^] would require the user to complete public key authentication, followed by either password or keyboard interactive authentication. Only methods that are next in one or more lists are offered at each stage, so for this @@ -102,10 +102,16 @@ DESCRIPTION For keyboard interactive authentication it is also possible to restrict authentication to a specific device by appending a colon - followed by the device identifier ``bsdauth'', ``pam'', or - ``skey'', depending on the server configuration. For example, - ``keyboard-interactive:bsdauth'' would restrict keyboard - interactive authentication to the ``bsdauth'' device. + followed by the device identifier M-bM-^@M-^\bsdauthM-bM-^@M-^], M-bM-^@M-^\pamM-bM-^@M-^], or M-bM-^@M-^\skeyM-bM-^@M-^], + depending on the server configuration. For example, + M-bM-^@M-^\keyboard-interactive:bsdauthM-bM-^@M-^] would restrict keyboard + interactive authentication to the M-bM-^@M-^\bsdauthM-bM-^@M-^] device. + + If the M-bM-^@M-^\publickeyM-bM-^@M-^] method is listed more than once, sshd(8) + verifies that keys that have been used successfully are not + reused for subsequent authentications. For example, an + AuthenticationMethods of M-bM-^@M-^\publickey,publickeyM-bM-^@M-^] will require + successful authentication using two different public keys. This option is only available for SSH protocol 2 and will yield a fatal error if enabled if protocol 1 is also enabled. Note that @@ -129,7 +135,9 @@ DESCRIPTION AuthorizedKeysCommandUser Specifies the user under whose account the AuthorizedKeysCommand is run. It is recommended to use a dedicated user that has no - other role on the host than running authorized keys commands. + other role on the host than running authorized keys commands. If + AuthorizedKeysCommand is specified but AuthorizedKeysCommandUser + is not, then sshd(8) will refuse to start. AuthorizedKeysFile Specifies the file that contains the public keys that can be used @@ -143,7 +151,7 @@ DESCRIPTION AuthorizedKeysFile is taken to be an absolute path or one relative to the user's home directory. Multiple files may be listed, separated by whitespace. The default is - ``.ssh/authorized_keys .ssh/authorized_keys2''. + M-bM-^@M-^\.ssh/authorized_keys .ssh/authorized_keys2M-bM-^@M-^]. AuthorizedPrincipalsFile Specifies a file that lists principal names that are accepted for @@ -152,7 +160,7 @@ DESCRIPTION which must appear in the certificate for it to be accepted for authentication. Names are listed one per line preceded by key options (as described in AUTHORIZED_KEYS FILE FORMAT in sshd(8)). - Empty lines and comments starting with `#' are ignored. + Empty lines and comments starting with M-bM-^@M-^X#M-bM-^@M-^Y are ignored. AuthorizedPrincipalsFile may contain tokens of the form %T which are substituted during connection setup. The following tokens @@ -162,7 +170,7 @@ DESCRIPTION AuthorizedPrincipalsFile is taken to be an absolute path or one relative to the user's home directory. - The default is ``none'', i.e. not to use a principals file - in + The default is M-bM-^@M-^\noneM-bM-^@M-^], i.e. not to use a principals file M-bM-^@M-^S in this case, the username of the user must appear in a certificate's principals list for it to be accepted. Note that AuthorizedPrincipalsFile is only used when authentication @@ -172,21 +180,22 @@ DESCRIPTION a similar facility (see sshd(8) for details). Banner The contents of the specified file are sent to the remote user - before authentication is allowed. If the argument is ``none'' - then no banner is displayed. This option is only available for + before authentication is allowed. If the argument is M-bM-^@M-^\noneM-bM-^@M-^] then + no banner is displayed. This option is only available for protocol version 2. By default, no banner is displayed. ChallengeResponseAuthentication Specifies whether challenge-response authentication is allowed (e.g. via PAM or through authentication styles supported in - login.conf(5)) The default is ``yes''. + login.conf(5)) The default is M-bM-^@M-^\yesM-bM-^@M-^]. ChrootDirectory Specifies the pathname of a directory to chroot(2) to after - authentication. All components of the pathname must be root- - owned directories that are not writable by any other user or - group. After the chroot, sshd(8) changes the working directory - to the user's home directory. + authentication. At session startup sshd(8) checks that all + components of the pathname are root-owned directories which are + not writable by any other user or group. After the chroot, + sshd(8) changes the working directory to the user's home + directory. The pathname may contain the following tokens that are expanded at runtime once the connecting user has been authenticated: %% is @@ -198,12 +207,17 @@ DESCRIPTION directories to support the user's session. For an interactive session this requires at least a shell, typically sh(1), and basic /dev nodes such as null(4), zero(4), stdin(4), stdout(4), - stderr(4), arandom(4) and tty(4) devices. For file transfer - sessions using ``sftp'', no additional configuration of the - environment is necessary if the in-process sftp server is used, - though sessions which use logging may require /dev/log inside the - chroot directory on some operating systems (see sftp-server(8) - for details). + stderr(4), and tty(4) devices. For file transfer sessions using + M-bM-^@M-^\sftpM-bM-^@M-^], no additional configuration of the environment is + necessary if the in-process sftp server is used, though sessions + which use logging may require /dev/log inside the chroot + directory on some operating systems (see sftp-server(8) for + details). + + For safety, it is very important that the directory hierarchy be + prevented from modification by other processes on the system + (especially those outside the jail). Misconfiguration can lead + to unsafe environments which sshd(8) cannot detect. The default is not to chroot(2). @@ -234,7 +248,7 @@ DESCRIPTION chacha20-poly1305@openssh.com The list of available ciphers may also be obtained using the -Q - option of ssh(1). + option of ssh(1) with an argument of M-bM-^@M-^\cipherM-bM-^@M-^]. ClientAliveCountMax Sets the number of client alive messages (see below) which may be @@ -264,8 +278,8 @@ DESCRIPTION Compression Specifies whether compression is allowed, or delayed until the - user has authenticated successfully. The argument must be - ``yes'', ``delayed'', or ``no''. The default is ``delayed''. + user has authenticated successfully. The argument must be M-bM-^@M-^\yesM-bM-^@M-^], + M-bM-^@M-^\delayedM-bM-^@M-^], or M-bM-^@M-^\noM-bM-^@M-^]. The default is M-bM-^@M-^\delayedM-bM-^@M-^]. DenyGroups This keyword can be followed by a list of group name patterns, @@ -291,6 +305,10 @@ DESCRIPTION See PATTERNS in ssh_config(5) for more information on patterns. + FingerprintHash + Specifies the hash algorithm used when logging key fingerprints. + Valid options are: M-bM-^@M-^\md5M-bM-^@M-^] and M-bM-^@M-^\sha256M-bM-^@M-^]. The default is M-bM-^@M-^\sha256M-bM-^@M-^]. + ForceCommand Forces the execution of the command specified by ForceCommand, ignoring any command supplied by the client and ~/.ssh/rc if @@ -299,7 +317,7 @@ DESCRIPTION execution. It is most useful inside a Match block. The command originally supplied by the client is available in the SSH_ORIGINAL_COMMAND environment variable. Specifying a command - of ``internal-sftp'' will force the use of an in-process sftp + of M-bM-^@M-^\internal-sftpM-bM-^@M-^] will force the use of an in-process sftp server that requires no support files when used with ChrootDirectory. @@ -310,37 +328,43 @@ DESCRIPTION hosts from connecting to forwarded ports. GatewayPorts can be used to specify that sshd should allow remote port forwardings to bind to non-loopback addresses, thus allowing other hosts to - connect. The argument may be ``no'' to force remote port - forwardings to be available to the local host only, ``yes'' to + connect. The argument may be M-bM-^@M-^\noM-bM-^@M-^] to force remote port + forwardings to be available to the local host only, M-bM-^@M-^\yesM-bM-^@M-^] to force remote port forwardings to bind to the wildcard address, or - ``clientspecified'' to allow the client to select the address to - which the forwarding is bound. The default is ``no''. + M-bM-^@M-^\clientspecifiedM-bM-^@M-^] to allow the client to select the address to + which the forwarding is bound. The default is M-bM-^@M-^\noM-bM-^@M-^]. GSSAPIAuthentication Specifies whether user authentication based on GSSAPI is allowed. - The default is ``no''. Note that this option applies to protocol + The default is M-bM-^@M-^\noM-bM-^@M-^]. Note that this option applies to protocol version 2 only. GSSAPICleanupCredentials Specifies whether to automatically destroy the user's credentials - cache on logout. The default is ``yes''. Note that this option + cache on logout. The default is M-bM-^@M-^\yesM-bM-^@M-^]. Note that this option applies to protocol version 2 only. + HostbasedAcceptedKeyTypes + Specifies the key types that will be accepted for hostbased + authentication as a comma-separated pattern list. The default + M-bM-^@M-^\*M-bM-^@M-^] will allow all key types. The -Q option of ssh(1) may be + used to list supported key types. + HostbasedAuthentication Specifies whether rhosts or /etc/hosts.equiv authentication together with successful public key client host authentication is allowed (host-based authentication). This option is similar to RhostsRSAAuthentication and applies to protocol version 2 only. - The default is ``no''. + The default is M-bM-^@M-^\noM-bM-^@M-^]. HostbasedUsesNameFromPacketOnly Specifies whether or not the server will attempt to perform a reverse name lookup when matching the name in the ~/.shosts, ~/.rhosts, and /etc/hosts.equiv files during - HostbasedAuthentication. A setting of ``yes'' means that sshd(8) + HostbasedAuthentication. A setting of M-bM-^@M-^\yesM-bM-^@M-^] means that sshd(8) uses the name supplied by the client rather than attempting to resolve the name from the TCP connection itself. The default is - ``no''. + M-bM-^@M-^\noM-bM-^@M-^]. HostCertificate Specifies a file containing a public host certificate. The @@ -355,70 +379,69 @@ DESCRIPTION /etc/ssh/ssh_host_ed25519_key and /etc/ssh/ssh_host_rsa_key for protocol version 2. Note that sshd(8) will refuse to use a file if it is group/world-accessible. It is possible to have multiple - host key files. ``rsa1'' keys are used for version 1 and - ``dsa'', ``ecdsa'', ``ed25519'' or ``rsa'' are used for version 2 - of the SSH protocol. It is also possible to specify public host - key files instead. In this case operations on the private key - will be delegated to an ssh-agent(1). + host key files. M-bM-^@M-^\rsa1M-bM-^@M-^] keys are used for version 1 and M-bM-^@M-^\dsaM-bM-^@M-^], + M-bM-^@M-^\ecdsaM-bM-^@M-^], M-bM-^@M-^\ed25519M-bM-^@M-^] or M-bM-^@M-^\rsaM-bM-^@M-^] are used for version 2 of the SSH + protocol. It is also possible to specify public host key files + instead. In this case operations on the private key will be + delegated to an ssh-agent(1). HostKeyAgent Identifies the UNIX-domain socket used to communicate with an agent that has access to the private host keys. If - ``SSH_AUTH_SOCK'' is specified, the location of the socket will - be read from the SSH_AUTH_SOCK environment variable. + M-bM-^@M-^\SSH_AUTH_SOCKM-bM-^@M-^] is specified, the location of the socket will be + read from the SSH_AUTH_SOCK environment variable. IgnoreRhosts Specifies that .rhosts and .shosts files will not be used in RhostsRSAAuthentication or HostbasedAuthentication. /etc/hosts.equiv and /etc/shosts.equiv are still used. The - default is ``yes''. + default is M-bM-^@M-^\yesM-bM-^@M-^]. IgnoreUserKnownHosts Specifies whether sshd(8) should ignore the user's ~/.ssh/known_hosts during RhostsRSAAuthentication or - HostbasedAuthentication. The default is ``no''. + HostbasedAuthentication. The default is M-bM-^@M-^\noM-bM-^@M-^]. IPQoS Specifies the IPv4 type-of-service or DSCP class for the - connection. Accepted values are ``af11'', ``af12'', ``af13'', - ``af21'', ``af22'', ``af23'', ``af31'', ``af32'', ``af33'', - ``af41'', ``af42'', ``af43'', ``cs0'', ``cs1'', ``cs2'', ``cs3'', - ``cs4'', ``cs5'', ``cs6'', ``cs7'', ``ef'', ``lowdelay'', - ``throughput'', ``reliability'', or a numeric value. This option - may take one or two arguments, separated by whitespace. If one - argument is specified, it is used as the packet class - unconditionally. If two values are specified, the first is - automatically selected for interactive sessions and the second - for non-interactive sessions. The default is ``lowdelay'' for - interactive sessions and ``throughput'' for non-interactive + connection. Accepted values are M-bM-^@M-^\af11M-bM-^@M-^], M-bM-^@M-^\af12M-bM-^@M-^], M-bM-^@M-^\af13M-bM-^@M-^], M-bM-^@M-^\af21M-bM-^@M-^], + M-bM-^@M-^\af22M-bM-^@M-^], M-bM-^@M-^\af23M-bM-^@M-^], M-bM-^@M-^\af31M-bM-^@M-^], M-bM-^@M-^\af32M-bM-^@M-^], M-bM-^@M-^\af33M-bM-^@M-^], M-bM-^@M-^\af41M-bM-^@M-^], M-bM-^@M-^\af42M-bM-^@M-^], M-bM-^@M-^\af43M-bM-^@M-^], + M-bM-^@M-^\cs0M-bM-^@M-^], M-bM-^@M-^\cs1M-bM-^@M-^], M-bM-^@M-^\cs2M-bM-^@M-^], M-bM-^@M-^\cs3M-bM-^@M-^], M-bM-^@M-^\cs4M-bM-^@M-^], M-bM-^@M-^\cs5M-bM-^@M-^], M-bM-^@M-^\cs6M-bM-^@M-^], M-bM-^@M-^\cs7M-bM-^@M-^], M-bM-^@M-^\efM-bM-^@M-^], + M-bM-^@M-^\lowdelayM-bM-^@M-^], M-bM-^@M-^\throughputM-bM-^@M-^], M-bM-^@M-^\reliabilityM-bM-^@M-^], or a numeric value. + This option may take one or two arguments, separated by + whitespace. If one argument is specified, it is used as the + packet class unconditionally. If two values are specified, the + first is automatically selected for interactive sessions and the + second for non-interactive sessions. The default is M-bM-^@M-^\lowdelayM-bM-^@M-^] + for interactive sessions and M-bM-^@M-^\throughputM-bM-^@M-^] for non-interactive sessions. KbdInteractiveAuthentication Specifies whether to allow keyboard-interactive authentication. - The argument to this keyword must be ``yes'' or ``no''. The - default is to use whatever value ChallengeResponseAuthentication - is set to (by default ``yes''). + The argument to this keyword must be M-bM-^@M-^\yesM-bM-^@M-^] or M-bM-^@M-^\noM-bM-^@M-^]. The default + is to use whatever value ChallengeResponseAuthentication is set + to (by default M-bM-^@M-^\yesM-bM-^@M-^]). KerberosAuthentication Specifies whether the password provided by the user for PasswordAuthentication will be validated through the Kerberos KDC. To use this option, the server needs a Kerberos servtab which allows the verification of the KDC's identity. The default - is ``no''. + is M-bM-^@M-^\noM-bM-^@M-^]. KerberosGetAFSToken If AFS is active and the user has a Kerberos 5 TGT, attempt to acquire an AFS token before accessing the user's home directory. - The default is ``no''. + The default is M-bM-^@M-^\noM-bM-^@M-^]. KerberosOrLocalPasswd If password authentication through Kerberos fails then the password will be validated via any additional local mechanism - such as /etc/passwd. The default is ``yes''. + such as /etc/passwd. The default is M-bM-^@M-^\yesM-bM-^@M-^]. KerberosTicketCleanup Specifies whether to automatically destroy the user's ticket - cache file on logout. The default is ``yes''. + cache file on logout. The default is M-bM-^@M-^\yesM-bM-^@M-^]. KexAlgorithms Specifies the available KEX (Key Exchange) algorithms. Multiple @@ -441,6 +464,9 @@ DESCRIPTION diffie-hellman-group-exchange-sha256, diffie-hellman-group14-sha1 + The list of available key exchange algorithms may also be + obtained using the -Q option of ssh(1) with an argument of M-bM-^@M-^\kexM-bM-^@M-^]. + KeyRegenerationInterval In protocol version 1, the ephemeral server key is automatically regenerated after this many seconds (if it has been used). The @@ -479,9 +505,9 @@ DESCRIPTION MACs Specifies the available MAC (message authentication code) algorithms. The MAC algorithm is used in protocol version 2 for data integrity protection. Multiple algorithms must be comma- - separated. The algorithms that contain ``-etm'' calculate the - MAC after encryption (encrypt-then-mac). These are considered - safer and their use recommended. The supported MACs are: + separated. The algorithms that contain M-bM-^@M-^\-etmM-bM-^@M-^] calculate the MAC + after encryption (encrypt-then-mac). These are considered safer + and their use recommended. The supported MACs are: hmac-md5 hmac-md5-96 @@ -509,12 +535,15 @@ DESCRIPTION umac-64@openssh.com,umac-128@openssh.com, hmac-sha2-256,hmac-sha2-512 + The list of available MAC algorithms may also be obtained using + the -Q option of ssh(1) with an argument of M-bM-^@M-^\macM-bM-^@M-^]. + Match Introduces a conditional block. If all of the criteria on the Match line are satisfied, the keywords on the following lines override those set in the global section of the config file, until either another Match line or the end of the file. If a - keyword appears in multiple Match blocks that are satisified, - only the first instance of the keyword is applied. + keyword appears in multiple Match blocks that are satisfied, only + the first instance of the keyword is applied. The arguments to Match are one or more criteria-pattern pairs or the single token All which matches all criteria. The available @@ -525,25 +554,28 @@ DESCRIPTION The patterns in an Address criteria may additionally contain addresses to match in CIDR address/masklen format, e.g. - ``192.0.2.0/24'' or ``3ffe:ffff::/32''. Note that the mask - length provided must be consistent with the address - it is an - error to specify a mask length that is too long for the address - or one with bits set in this host portion of the address. For - example, ``192.0.2.0/33'' and ``192.0.2.0/8'' respectively. + M-bM-^@M-^\192.0.2.0/24M-bM-^@M-^] or M-bM-^@M-^\3ffe:ffff::/32M-bM-^@M-^]. Note that the mask length + provided must be consistent with the address - it is an error to + specify a mask length that is too long for the address or one + with bits set in this host portion of the address. For example, + M-bM-^@M-^\192.0.2.0/33M-bM-^@M-^] and M-bM-^@M-^\192.0.2.0/8M-bM-^@M-^] respectively. Only a subset of keywords may be used on the lines following a Match keyword. Available keywords are AcceptEnv, - AllowAgentForwarding, AllowGroups, AllowTcpForwarding, - AllowUsers, AuthenticationMethods, AuthorizedKeysCommand, - AuthorizedKeysCommandUser, AuthorizedKeysFile, - AuthorizedPrincipalsFile, Banner, ChrootDirectory, DenyGroups, - DenyUsers, ForceCommand, GatewayPorts, GSSAPIAuthentication, - HostbasedAuthentication, HostbasedUsesNameFromPacketOnly, + AllowAgentForwarding, AllowGroups, AllowStreamLocalForwarding, + AllowTcpForwarding, AllowUsers, AuthenticationMethods, + AuthorizedKeysCommand, AuthorizedKeysCommandUser, + AuthorizedKeysFile, AuthorizedPrincipalsFile, Banner, + ChrootDirectory, DenyGroups, DenyUsers, ForceCommand, + GatewayPorts, GSSAPIAuthentication, HostbasedAcceptedKeyTypes, + HostbasedAuthentication, HostbasedUsesNameFromPacketOnly, IPQoS, KbdInteractiveAuthentication, KerberosAuthentication, MaxAuthTries, MaxSessions, PasswordAuthentication, PermitEmptyPasswords, PermitOpen, PermitRootLogin, PermitTTY, - PermitTunnel, PermitUserRC, PubkeyAuthentication, RekeyLimit, - RhostsRSAAuthentication, RSAAuthentication, X11DisplayOffset, + PermitTunnel, PermitUserRC, PubkeyAcceptedKeyTypes, + PubkeyAuthentication, RekeyLimit, RevokedKeys, + RhostsRSAAuthentication, RSAAuthentication, StreamLocalBindMask, + StreamLocalBindUnlink, TrustedUserCAKeys, X11DisplayOffset, X11Forwarding and X11UseLocalHost. MaxAuthTries @@ -562,21 +594,21 @@ DESCRIPTION expires for a connection. The default is 10:30:100. Alternatively, random early drop can be enabled by specifying the - three colon separated values ``start:rate:full'' (e.g. - "10:30:60"). sshd(8) will refuse connection attempts with a - probability of ``rate/100'' (30%) if there are currently - ``start'' (10) unauthenticated connections. The probability - increases linearly and all connection attempts are refused if the - number of unauthenticated connections reaches ``full'' (60). + three colon separated values M-bM-^@M-^\start:rate:fullM-bM-^@M-^] (e.g. "10:30:60"). + sshd(8) will refuse connection attempts with a probability of + M-bM-^@M-^\rate/100M-bM-^@M-^] (30%) if there are currently M-bM-^@M-^\startM-bM-^@M-^] (10) + unauthenticated connections. The probability increases linearly + and all connection attempts are refused if the number of + unauthenticated connections reaches M-bM-^@M-^\fullM-bM-^@M-^] (60). PasswordAuthentication Specifies whether password authentication is allowed. The - default is ``yes''. + default is M-bM-^@M-^\yesM-bM-^@M-^]. PermitEmptyPasswords When password authentication is allowed, it specifies whether the server allows login to accounts with empty password strings. The - default is ``no''. + default is M-bM-^@M-^\noM-bM-^@M-^]. PermitOpen Specifies the destinations to which TCP port forwarding is @@ -588,47 +620,50 @@ DESCRIPTION PermitOpen [IPv6_addr]:port Multiple forwards may be specified by separating them with - whitespace. An argument of ``any'' can be used to remove all + whitespace. An argument of M-bM-^@M-^\anyM-bM-^@M-^] can be used to remove all restrictions and permit any forwarding requests. An argument of - ``none'' can be used to prohibit all forwarding requests. By + M-bM-^@M-^\noneM-bM-^@M-^] can be used to prohibit all forwarding requests. By default all port forwarding requests are permitted. PermitRootLogin Specifies whether root can log in using ssh(1). The argument - must be ``yes'', ``without-password'', ``forced-commands-only'', - or ``no''. The default is ``yes''. + must be M-bM-^@M-^\yesM-bM-^@M-^], M-bM-^@M-^\without-passwordM-bM-^@M-^], M-bM-^@M-^\forced-commands-onlyM-bM-^@M-^], or + M-bM-^@M-^\noM-bM-^@M-^]. The default is M-bM-^@M-^\yesM-bM-^@M-^]. - If this option is set to ``without-password'', password + If this option is set to M-bM-^@M-^\without-passwordM-bM-^@M-^], password authentication is disabled for root. - If this option is set to ``forced-commands-only'', root login - with public key authentication will be allowed, but only if the + If this option is set to M-bM-^@M-^\forced-commands-onlyM-bM-^@M-^], root login with + public key authentication will be allowed, but only if the command option has been specified (which may be useful for taking remote backups even if root login is normally not allowed). All other authentication methods are disabled for root. - If this option is set to ``no'', root is not allowed to log in. + If this option is set to M-bM-^@M-^\noM-bM-^@M-^], root is not allowed to log in. PermitTunnel Specifies whether tun(4) device forwarding is allowed. The - argument must be ``yes'', ``point-to-point'' (layer 3), - ``ethernet'' (layer 2), or ``no''. Specifying ``yes'' permits - both ``point-to-point'' and ``ethernet''. The default is ``no''. + argument must be M-bM-^@M-^\yesM-bM-^@M-^], M-bM-^@M-^\point-to-pointM-bM-^@M-^] (layer 3), M-bM-^@M-^\ethernetM-bM-^@M-^] + (layer 2), or M-bM-^@M-^\noM-bM-^@M-^]. Specifying M-bM-^@M-^\yesM-bM-^@M-^] permits both + M-bM-^@M-^\point-to-pointM-bM-^@M-^] and M-bM-^@M-^\ethernetM-bM-^@M-^]. The default is M-bM-^@M-^\noM-bM-^@M-^]. + + Independent of this setting, the permissions of the selected + tun(4) device must allow access to the user. PermitTTY Specifies whether pty(4) allocation is permitted. The default is - ``yes''. + M-bM-^@M-^\yesM-bM-^@M-^]. PermitUserEnvironment Specifies whether ~/.ssh/environment and environment= options in ~/.ssh/authorized_keys are processed by sshd(8). The default is - ``no''. Enabling environment processing may enable users to - bypass access restrictions in some configurations using - mechanisms such as LD_PRELOAD. + M-bM-^@M-^\noM-bM-^@M-^]. Enabling environment processing may enable users to bypass + access restrictions in some configurations using mechanisms such + as LD_PRELOAD. PermitUserRC Specifies whether any ~/.ssh/rc file is executed. The default is - ``yes''. + M-bM-^@M-^\yesM-bM-^@M-^]. PidFile Specifies the file that contains the process ID of the SSH @@ -641,24 +676,30 @@ DESCRIPTION PrintLastLog Specifies whether sshd(8) should print the date and time of the last user login when a user logs in interactively. The default - is ``yes''. + is M-bM-^@M-^\yesM-bM-^@M-^]. PrintMotd Specifies whether sshd(8) should print /etc/motd when a user logs in interactively. (On some systems it is also printed by the - shell, /etc/profile, or equivalent.) The default is ``yes''. + shell, /etc/profile, or equivalent.) The default is M-bM-^@M-^\yesM-bM-^@M-^]. Protocol Specifies the protocol versions sshd(8) supports. The possible - values are `1' and `2'. Multiple versions must be comma- - separated. The default is `2'. Note that the order of the + values are M-bM-^@M-^X1M-bM-^@M-^Y and M-bM-^@M-^X2M-bM-^@M-^Y. Multiple versions must be comma- + separated. The default is M-bM-^@M-^X2M-bM-^@M-^Y. Note that the order of the protocol list does not indicate preference, because the client selects among multiple protocol versions offered by the server. - Specifying ``2,1'' is identical to ``1,2''. + Specifying M-bM-^@M-^\2,1M-bM-^@M-^] is identical to M-bM-^@M-^\1,2M-bM-^@M-^]. + + PubkeyAcceptedKeyTypes + Specifies the key types that will be accepted for public key + authentication as a comma-separated pattern list. The default + M-bM-^@M-^\*M-bM-^@M-^] will allow all key types. The -Q option of ssh(1) may be + used to list supported key types. PubkeyAuthentication Specifies whether public key authentication is allowed. The - default is ``yes''. Note that this option applies to protocol + default is M-bM-^@M-^\yesM-bM-^@M-^]. Note that this option applies to protocol version 2 only. RekeyLimit @@ -666,12 +707,12 @@ DESCRIPTION before the session key is renegotiated, optionally followed a maximum amount of time that may pass before the session key is renegotiated. The first argument is specified in bytes and may - have a suffix of `K', `M', or `G' to indicate Kilobytes, + have a suffix of M-bM-^@M-^XKM-bM-^@M-^Y, M-bM-^@M-^XMM-bM-^@M-^Y, or M-bM-^@M-^XGM-bM-^@M-^Y to indicate Kilobytes, Megabytes, or Gigabytes, respectively. The default is between - `1G' and `4G', depending on the cipher. The optional second + M-bM-^@M-^X1GM-bM-^@M-^Y and M-bM-^@M-^X4GM-bM-^@M-^Y, depending on the cipher. The optional second value is specified in seconds and may use any of the units documented in the TIME FORMATS section. The default value for - RekeyLimit is ``default none'', which means that rekeying is + RekeyLimit is M-bM-^@M-^\default noneM-bM-^@M-^], which means that rekeying is performed after the cipher's default amount of data has been sent or received and no time based rekeying is done. This option applies to protocol version 2 only. @@ -688,12 +729,11 @@ DESCRIPTION RhostsRSAAuthentication Specifies whether rhosts or /etc/hosts.equiv authentication together with successful RSA host authentication is allowed. The - default is ``no''. This option applies to protocol version 1 - only. + default is M-bM-^@M-^\noM-bM-^@M-^]. This option applies to protocol version 1 only. RSAAuthentication Specifies whether pure RSA authentication is allowed. The - default is ``yes''. This option applies to protocol version 1 + default is M-bM-^@M-^\yesM-bM-^@M-^]. This option applies to protocol version 1 only. ServerKeyBits @@ -719,14 +759,14 @@ DESCRIPTION domain socket file. This option is only used for port forwarding to a Unix-domain socket file. - The argument must be ``yes'' or ``no''. The default is ``no''. + The argument must be M-bM-^@M-^\yesM-bM-^@M-^] or M-bM-^@M-^\noM-bM-^@M-^]. The default is M-bM-^@M-^\noM-bM-^@M-^]. StrictModes Specifies whether sshd(8) should check file modes and ownership of the user's files and home directory before accepting login. This is normally desirable because novices sometimes accidentally leave their directory or files world-writable. The default is - ``yes''. Note that this does not apply to ChrootDirectory, whose + M-bM-^@M-^\yesM-bM-^@M-^]. Note that this does not apply to ChrootDirectory, whose permissions and ownership are checked unconditionally. Subsystem @@ -734,11 +774,11 @@ DESCRIPTION Arguments should be a subsystem name and a command (with optional arguments) to execute upon subsystem request. - The command sftp-server(8) implements the ``sftp'' file transfer + The command sftp-server(8) implements the M-bM-^@M-^\sftpM-bM-^@M-^] file transfer subsystem. - Alternately the name ``internal-sftp'' implements an in-process - ``sftp'' server. This may simplify configurations using + Alternately the name M-bM-^@M-^\internal-sftpM-bM-^@M-^] implements an in-process + M-bM-^@M-^\sftpM-bM-^@M-^] server. This may simplify configurations using ChrootDirectory to force a different filesystem root on clients. By default no subsystems are defined. Note that this option @@ -757,21 +797,21 @@ DESCRIPTION this means that connections will die if the route is down temporarily, and some people find it annoying. On the other hand, if TCP keepalives are not sent, sessions may hang - indefinitely on the server, leaving ``ghost'' users and consuming + indefinitely on the server, leaving M-bM-^@M-^\ghostM-bM-^@M-^] users and consuming server resources. - The default is ``yes'' (to send TCP keepalive messages), and the + The default is M-bM-^@M-^\yesM-bM-^@M-^] (to send TCP keepalive messages), and the server will notice if the network goes down or the client host crashes. This avoids infinitely hanging sessions. To disable TCP keepalive messages, the value should be set to - ``no''. + M-bM-^@M-^\noM-bM-^@M-^]. TrustedUserCAKeys Specifies a file containing public keys of certificate authorities that are trusted to sign user certificates for authentication. Keys are listed one per line; empty lines and - comments starting with `#' are allowed. If a certificate is + comments starting with M-bM-^@M-^X#M-bM-^@M-^Y are allowed. If a certificate is presented for authentication and has its signing CA key listed in this file, then it may be used for authentication for any user listed in the certificate's principals list. Note that @@ -781,18 +821,18 @@ DESCRIPTION UseDNS Specifies whether sshd(8) should look up the remote host name and check that the resolved host name for the remote IP address maps - back to the very same IP address. The default is ``yes''. + back to the very same IP address. The default is M-bM-^@M-^\noM-bM-^@M-^]. UseLogin Specifies whether login(1) is used for interactive login - sessions. The default is ``no''. Note that login(1) is never - used for remote command execution. Note also, that if this is + sessions. The default is M-bM-^@M-^\noM-bM-^@M-^]. Note that login(1) is never used + for remote command execution. Note also, that if this is enabled, X11Forwarding will be disabled because login(1) does not know how to handle xauth(1) cookies. If UsePrivilegeSeparation is specified, it will be disabled after authentication. UsePAM Enables the Pluggable Authentication Module interface. If set to - ``yes'' this will enable PAM authentication using + M-bM-^@M-^\yesM-bM-^@M-^] this will enable PAM authentication using ChallengeResponseAuthentication and PasswordAuthentication in addition to PAM account and session module processing for all authentication types. @@ -802,7 +842,7 @@ DESCRIPTION either PasswordAuthentication or ChallengeResponseAuthentication. If UsePAM is enabled, you will not be able to run sshd(8) as a - non-root user. The default is ``no''. + non-root user. The default is M-bM-^@M-^\noM-bM-^@M-^]. UsePrivilegeSeparation Specifies whether sshd(8) separates privileges by creating an @@ -811,14 +851,14 @@ DESCRIPTION that has the privilege of the authenticated user. The goal of privilege separation is to prevent privilege escalation by containing any corruption within the unprivileged processes. The - default is ``yes''. If UsePrivilegeSeparation is set to - ``sandbox'' then the pre-authentication unprivileged process is - subject to additional restrictions. + default is M-bM-^@M-^\yesM-bM-^@M-^]. If UsePrivilegeSeparation is set to M-bM-^@M-^\sandboxM-bM-^@M-^] + then the pre-authentication unprivileged process is subject to + additional restrictions. VersionAddendum Optionally specifies additional text to append to the SSH protocol banner sent by the server upon connection. The default - is ``none''. + is M-bM-^@M-^\noneM-bM-^@M-^]. X11DisplayOffset Specifies the first display number available for sshd(8)'s X11 @@ -827,7 +867,7 @@ DESCRIPTION X11Forwarding Specifies whether X11 forwarding is permitted. The argument must - be ``yes'' or ``no''. The default is ``no''. + be M-bM-^@M-^\yesM-bM-^@M-^] or M-bM-^@M-^\noM-bM-^@M-^]. The default is M-bM-^@M-^\noM-bM-^@M-^]. When X11 forwarding is enabled, there may be additional exposure to the server and to client displays if the sshd(8) proxy display @@ -841,7 +881,7 @@ DESCRIPTION ssh_config(5)). A system administrator may have a stance in which they want to protect clients that may expose themselves to attack by unwittingly requesting X11 forwarding, which can - warrant a ``no'' setting. + warrant a M-bM-^@M-^\noM-bM-^@M-^] setting. Note that disabling X11 forwarding does not prevent users from forwarding X11 traffic, as users can always install their own @@ -853,12 +893,12 @@ DESCRIPTION to the loopback address or to the wildcard address. By default, sshd binds the forwarding server to the loopback address and sets the hostname part of the DISPLAY environment variable to - ``localhost''. This prevents remote hosts from connecting to the + M-bM-^@M-^\localhostM-bM-^@M-^]. This prevents remote hosts from connecting to the proxy display. However, some older X11 clients may not function - with this configuration. X11UseLocalhost may be set to ``no'' to + with this configuration. X11UseLocalhost may be set to M-bM-^@M-^\noM-bM-^@M-^] to specify that the forwarding server should be bound to the - wildcard address. The argument must be ``yes'' or ``no''. The - default is ``yes''. + wildcard address. The argument must be M-bM-^@M-^\yesM-bM-^@M-^] or M-bM-^@M-^\noM-bM-^@M-^]. The + default is M-bM-^@M-^\yesM-bM-^@M-^]. XAuthLocation Specifies the full pathname of the xauth(1) program. The default @@ -870,7 +910,7 @@ TIME FORMATS time[qualifier], where time is a positive integer value and qualifier is one of the following: - <none> seconds + M-bM-^_M-(noneM-bM-^_M-) seconds s | S seconds m | M minutes h | H hours @@ -903,4 +943,4 @@ AUTHORS versions 1.5 and 2.0. Niels Provos and Markus Friedl contributed support for privilege separation. -OpenBSD 5.6 July 28, 2014 OpenBSD 5.6 +OpenBSD 5.7 February 20, 2015 OpenBSD 5.7 |
