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Appendix A Server Configuration File Syntax

The DTD of the server configuration file is shown below:

<!--									-->
<!--									-->
<!-- secsh-server.dtd							-->
<!--									-->
<!-- Copyright (c) Tectia Corporation.                             -->
<!-- This software is protected by international copyright laws.   -->
<!-- All rights reserved.                                          -->
<!--									-->
<!-- Document type definition for the Tectia Server XML		-->
<!-- configuration files.						-->
<!--									-->
<!--									-->

<!-- Tunable parameters used in the policy. -->

<!-- Default connection action. -->
<!ENTITY default-connection-action			"allow">

<!-- Default terminal action. -->
<!ENTITY default-terminal-action			"allow">

<!-- Default subsystem action. -->
<!ENTITY default-subsystem-action			"allow">

<!-- Default subsystem audit value. -->
<!ENTITY default-subsystem-audit			"yes">

<!-- Default for allowing undefined blackboard entries by selectors. -->
<!ENTITY default-allow-undefined-value			"no">

<!-- Default user-privileged value. -->
<!ENTITY default-user-privileged-value			"yes">

<!-- Default user-password-change-needed value. -->
<!ENTITY default-user-password-change-needed-value	"yes">

<!-- Reverse mapping is not required by default in 
     publickey authentication. -->
<!ENTITY default-auth-publickey-require-dns-match       "no">

<!-- Default tunnel action. -->
<!ENTITY default-tunnel-action				"allow">

<!-- Default command action. -->
<!ENTITY default-command-action				"allow">

<!-- Default interactive command action. -->
<!ENTITY default-interactive-command-action		"no">

<!-- Default rekey interval in seconds. -->
<!ENTITY default-rekey-interval-seconds			"3600">

<!-- Default rekey interval in bytes (1GB). -->
<!ENTITY default-rekey-interval-bytes			"1000000000">

<!-- Default login grace time in seconds. -->
<!ENTITY default-login-grace-time-seconds		"600">

<!-- Default authentication action. -->
<!ENTITY default-authentication-action			"allow">

<!-- Password authentication default failure delay in seconds. -->
<!ENTITY default-auth-password-failure-delay		"2">

<!-- Password authentication default maximum tries. -->
<!ENTITY default-auth-password-max-tries		"3">

<!-- DNS match not required by default in host-based authentication. -->
<!ENTITY default-auth-hostbased-require-dns-match	"no">

<!-- Keyboard-interactive authentication default failure delay in seconds. -->
<!ENTITY default-auth-kbdint-failure-delay		"2">

<!-- Keyboard-interactive authentication default maximum tries. -->
<!ENTITY default-auth-kbdint-max-tries			"3">

<!-- Keyboard-interactive RADIUS server default port. -->
<!ENTITY default-radius-server-port			"1812">

<!-- Keyboard-interactive RADIUS server default UDP recvfrom timeout. -->
<!ENTITY default-radius-server-timeout			"10">

<!-- GSSAPI default ticket forwarding policy. -->
<!ENTITY default-gssapi-ticket-forwarding-policy	"no">

<!-- Default time in seconds for using expired CRLs. -->
<!ENTITY default-use-expired-crls			"0">

<!-- CRLs are not disabled by default. -->
<!ENTITY default-disable-crls				"no">

<!-- DoD PKI compatibility is not required by default. -->
<!ENTITY default-dod-pki				"no">

<!-- LDAP server default port. -->
<!ENTITY default-ldap-server-port			"389">

<!-- Default CRL update minimum interval. -->
<!ENTITY default-crl-update-min-interval		"30">

<!-- Default interval for CRL prefetching. -->
<!ENTITY default-crl-prefetch-interval			"3600">

<!-- Default crypto library mode ("fips" or "standard"). -->
<!ENTITY default-crypto-lib-mode			"standard">

<!-- Both ipv4 and ipv6 are enabled by default -->
<!ENTITY default-address-family-type			"any">

<!-- Default log event facility. -->
<!ENTITY default-log-event-facility			"normal">

<!-- Default log event severity. -->
<!ENTITY default-log-event-severity			"notice">

<!-- Default values for password caching. -->
<!ENTITY default-password-cache-max-passwords		"2000">
<!ENTITY default-password-cache-expiration-time		"0">
<!ENTITY default-password-cache-by-default		"no">

<!ENTITY default-access-action				"allow">

<!-- Default ignore AIX rlogin setting. -->
<!ENTITY default-ignore-aix-rlogin              	"no">

<!-- Default ignore AIX login setting. -->
<!ENTITY default-ignore-aix-login                   	"no">

<!-- Default record sessions without PTYs. -->
<!ENTITY default-record-ptyless-sessions              	"yes">

<!-- Default Windows logon type. -->
<!ENTITY default-windows-logon-type              	"interactive">

<!-- Default Windows terminal mode. -->
<!ENTITY default-windows-terminal-mode			"console">

<!-- Default Ignore nisplus no permission error. -->
<!ENTITY default-ignore-nisplus-no-permission           "no">

<!-- TCP keepalives are disabled by default. -->
<!ENTITY default-tcp-keepalive				"no">

<!-- Whether a plugin is allowed to not initialize (due to e.g. -->
<!-- system configuration, missing shared libraries).           -->
<!ENTITY default-allow-missing				"no">

<!-- Default connection idle timeout in seconds.  The value zero -->
<!-- disables idle timeout. -->
<!ENTITY default-idle-timeout				"0">

<!-- Message of the day (MOTD) is printed on login by default. -->
<!ENTITY default-print-motd				"yes">

<!-- Authentication file permissions are checked by default. -->
<!ENTITY default-strict-modes				"yes">

<!-- Default authentication file permission mask bits (octal). -->
<!ENTITY default-mask-bits				"022">

<!-- Service name used with PAM. -->
<!ENTITY default-pam-service-name			"ssh-server-g3">
<!-- Whether to perform PAM Account and Session management when executing -->
<!-- commands, i.e. shells, subsystems and remote commands.               -->
<!ENTITY default-pam-command-action			"no">

<!-- Whether to bind x11 listeners to the localhost interface or to the   -->
<!-- 'any' interface. If the x11 listener is bound to the 'any' interface -->
<!-- the SO_REUSEADDR socket option will not be set.                      --> 
<!ENTITY default-x11-listen-address                     "localhost">

<!-- Whether to only use PAM to check if the user is allowed to login.    -->
<!-- PAM can be used during authentication or via the                     -->
<!-- pam-calls-with-commands setting. If PAM is not used in either        -->
<!-- authentication or with pam-calls-with-commands the normal system     -->
<!-- checks will be used to determine whether the user is allowed to      -->
<!-- login i.e. account is not locked etc.                                -->
<!ENTITY default-pam-account-checking-only              "no">

<!-- Whether the server tries to resolve the client hostname during       -->
<!-- connection setup                                                     -->
<!ENTITY default-resolve-client-hostname                "yes">

<!-- Whether to suppress last login, password expiry, motd etc. messages  -->
<!-- during login.                                                        -->
<!ENTITY default-quiet-login                            "no">

<!-- Default certificate cache size in MBs. -->
<!ENTITY default-cert-cache-size                        "35">

<!-- Default CRL size limit (in MB). -->
<!ENTITY default-max-crl-size                           "11">

<!-- The default maximum path length for certificate validation. -->
<!ENTITY default-max-path-length                        "10">

<!-- Default timeout for external searches (LDAP, HTTP, OCSP) (seconds). -->
<!ENTITY default-external-search-timeout                "60">

<!-- Default limit of LDAP responses (MBs). -->
<!ENTITY default-max-ldap-response-length               "11">

<!-- Default LDAP connection idle timeout in seconds. -->
<!ENTITY default-ldap-idle-timeout                      "30">

<!-- Whether to enable AIX LAM password change by default. -->
<!ENTITY default-aix-lam-password-change                "no">

<!-- Policy elements. -->

<!-- The top-level element. -->
<!ELEMENT secsh-server	(params?,connections?,authentication-methods?

<!-- Parameter element. Only "hostkey" and "listener" are allowed multiple -->
<!-- times.                                                                -->
<!ELEMENT params (crypto-lib|address-family|hostkey|listener|settings|domain-policy

<!-- Cryptographic library. -->
<!ELEMENT crypto-lib	EMPTY>
<!ATTLIST crypto-lib
	  mode		(fips|standard) "&default-crypto-lib-mode;">

<!-- address-family mode setting ipv4 & ipv6-->
<!ELEMENT address-family	EMPTY>
<!ATTLIST address-family
	  type		(any|inet|inet6) "&default-address-family-type;">

<!-- Settings - a block for stuff that is too minor to have its
     own element in the params block. -->
<!ELEMENT settings	EMPTY>
<!ATTLIST settings
	  signature-algorithms    CDATA    #IMPLIED
	  proxy-scheme		  CDATA	   #IMPLIED
	  xauth-path		  CDATA	   #IMPLIED
	  x11-listen-address      (localhost|any) 
	  pam-account-checking-only (yes|no) 
	  ignore-aix-rlogin	  (yes|no) "&default-ignore-aix-rlogin;"
	  ignore-aix-login	  (yes|no) "&default-ignore-aix-login;"
	  record-ptyless-sessions (yes|no) "&default-record-ptyless-sessions;"
          user-config-dir	  CDATA	   #IMPLIED
          default-path		  CDATA	   #IMPLIED
	  windows-logon-type      (batch|interactive|network|network-cleartext)
	  windows-terminal-mode	  (console|stream)
          ignore-nisplus-no-permission (yes|no) 
          resolve-client-hostname (yes|no) "&default-resolve-client-hostname;"
	  quiet-login             (yes|no) "&default-quiet-login;"
          default-domain	  CDATA	   #IMPLIED>

<!ELEMENT pluggable-authentication-modules EMPTY>
<!ATTLIST pluggable-authentication-modules
	  service-name		  CDATA		"&default-pam-service-name;"
	  dll-path                CDATA		#IMPLIED
	  pam-calls-with-commands (yes|no)	"&default-pam-command-action;">

<!ELEMENT protocol-parameters EMPTY>
<!ATTLIST protocol-parameters
	  threads CDATA #IMPLIED>

<!-- Hostkey specification. -->
<!ELEMENT hostkey	((private,(public|x509-certificate)?)|externalkey)>

<!-- Private key specification. -->
<!ELEMENT private	(#PCDATA)>
<!ATTLIST private
	  file		CDATA	#IMPLIED>

<!-- Public key. -->
<!ELEMENT public	(#PCDATA)>
<!ATTLIST public
	  file		CDATA	#IMPLIED>

<!-- Certificate (host). -->
<!ELEMENT x509-certificate	(#PCDATA)>
<!ATTLIST x509-certificate
	  file		CDATA	#IMPLIED>

<!-- External key. -->
<!ELEMENT externalkey	EMPTY>
<!ATTLIST externalkey
	  init-info	CDATA	#IMPLIED>

<!-- CA certificate. -->
<!ELEMENT ca-certificate	(#PCDATA)>
<!ATTLIST ca-certificate
	  file			CDATA		#IMPLIED
	  name			CDATA		#REQUIRED
	  disable-crls		(yes|no)	"&default-disable-crls;"
	  use-expired-crls	CDATA		"&default-use-expired-crls;"
	  trusted		(yes|no)	"yes">

<!-- Certificate caching. -->
<!ELEMENT cert-cache-file	EMPTY>
<!ATTLIST cert-cache-file
	  file			CDATA	#REQUIRED>

<!-- CRL automatic updating. -->
<!ELEMENT crl-auto-update	EMPTY>
<!ATTLIST crl-auto-update
	  update-before		CDATA	#IMPLIED
	  minimum-interval	CDATA	"&default-crl-update-min-interval;">

<!-- CRL prefetch. -->
<!ELEMENT crl-prefetch		EMPTY>
<!ATTLIST crl-prefetch
	  interval		CDATA	"&default-crl-prefetch-interval;"

<!-- LDAP server. -->
<!ELEMENT ldap-server		EMPTY>
<!ATTLIST ldap-server
	  address		CDATA	#REQUIRED
	  port			CDATA	"&default-ldap-server-port;">

<!-- OCSP responder. -->
<!ELEMENT ocsp-responder	(#PCDATA)>
<!ATTLIST ocsp-responder
	  validity-period	CDATA	#IMPLIED

<!-- Enable DoD PKI compliancy. -->
<!ELEMENT dod-pki		EMPTY>
<!ATTLIST dod-pki
	  enable	(yes|no)	"&default-dod-pki;">

<!-- Secure Shell server TCP listener address and port. -->
<!ELEMENT listener	EMPTY>
<!ATTLIST listener
	  port		CDATA	"22"
	  address	CDATA	#IMPLIED>

<!-- Server domain policy type -->
<!ELEMENT domain-policy			EMPTY>
<!ATTLIST domain-policy
	  windows-domain-precedence	CDATA	#IMPLIED>

<!-- Logging. -->
<!ELEMENT logging	(log-events*)>

<!-- Log events. -->
<!ELEMENT log-events	(#PCDATA)>
<!ATTLIST log-events
	  facility	(normal|daemon|user|auth|local0|local1
	  severity	(informational|notice|warning|error|critical

<!-- Certificate validation. Maximum one of each of "cert-cache-file", -->
<!-- "crl-auto-update" and "dod-pki" can be present.                   -->
<!ELEMENT cert-validation (ldap-server|ocsp-responder|cert-cache-file

<!ATTLIST cert-validation
	  http-proxy-url	CDATA	#IMPLIED
	  socks-server-url	CDATA	#IMPLIED
	  cache-size            CDATA   "&default-cert-cache-size;"
	  max-crl-size          CDATA   "&default-max-crl-size;"
	  external-search-timeout CDATA   "&default-external-search-timeout;"
	  max-ldap-response-length CDATA   "&default-max-ldap-response-length;"
	  ldap-idle-timeout     CDATA   "&default-ldap-idle-timeout;"
	  max-path-length       CDATA   "&default-max-path-length;">

<!-- Password caching. -->
<!ELEMENT password-cache (access*)>

<!ATTLIST password-cache
          file                CDATA   #IMPLIED
	  max-passwords       CDATA   "&default-password-cache-max-passwords;"
	  expiration-time     CDATA
          cache-by-default    (yes|no)


<!ATTLIST access
          user                CDATA   #REQUIRED
          action              (allow|deny)	"&default-access-action;">

<!-- Limits. -->
<!-- max-connections is _per_servant_ .-->
<!-- servant-lifetime    - how many connections a servant will handle -->
<!-- before it is retired. -->

<!ELEMENT limits		(servant-lifetime)*>
<!ATTLIST limits
	  max-connections	CDATA	#IMPLIED
	  max-processes		CDATA	#IMPLIED>

<!ELEMENT servant-lifetime	EMPTY>
<!ATTLIST servant-lifetime
	  total-connections	CDATA	#IMPLIED>

<!-- Connections. -->
<!ELEMENT connections	(connection+)>

<!-- Connection. -->
<!ELEMENT connection	(selector*,rekey?,cipher*,mac*,kex*,hostkey-algorithm*)>
<!ATTLIST connection
	  name		ID			#IMPLIED
	  action	(allow|deny)		"&default-connection-action;"
	  tcp-keepalive (yes|no)		"&default-tcp-keepalive;">

<!-- Rekey intervals. -->
<!ATTLIST rekey
	  seconds	CDATA	"&default-rekey-interval-seconds;"
	  bytes		CDATA	"&default-rekey-interval-bytes;">

<!-- Cipher. -->
<!ATTLIST cipher
	  name	        CDATA	                #REQUIRED
          allow-missing (yes|no)                "&default-allow-missing;">

<!-- MAC. -->
	  name	        CDATA	                #REQUIRED
          allow-missing (yes|no)                "&default-allow-missing;">

<!-- KEX. -->
	  name	        CDATA	                #REQUIRED
          allow-missing (yes|no)                "&default-allow-missing;">

<!-- Hostkey algorithm. -->
<!ELEMENT hostkey-algorithm  EMPTY>
<!ATTLIST hostkey-algorithm
	  name          CDATA                   #REQUIRED
	  allow-missing (yes|no)                "&default-allow-missing;">

<!-- Selector element. -->
<!ELEMENT selector	(interface|certificate|host-certificate|ip

<!-- Interface selector. At least one parameter must be given. If id is -->
<!-- set, the others MUST NOT be set. If id is not set, either or both	-->
<!-- of address and port may be defined.				-->
<!ELEMENT interface	  EMPTY>
<!ATTLIST interface
	  id		  IDREF	   #IMPLIED
	  address	  CDATA	   #IMPLIED
	  port		  CDATA    #IMPLIED
	  allow-undefined (yes|no) "&default-allow-undefined-value;">

<!-- Public key (plain) passed selector. -->
<!ELEMENT publickey-passed	EMPTY>
<!ATTLIST publickey-passed
	  length		CDATA	 #IMPLIED
	  allow-undefined 	(yes|no)

<!-- Certificate selector. -->
<!ELEMENT certificate	EMPTY>
<!ATTLIST certificate
	  field		  (ca-list|issuer-name|subject-name|serial-number
			   |extended-key-usage)	#REQUIRED
	  pattern		 CDATA	#IMPLIED
	  pattern-case-sensitive CDATA	#IMPLIED
	  regexp		 CDATA	#IMPLIED
	  ignore-prefix          (yes|no) #IMPLIED
	  ignore-suffix          (yes|no) #IMPLIED
	  explicit		 (yes|no) #IMPLIED
	  allow-undefined 	 (yes|no)

<!-- Host certificate selector. -->
<!ELEMENT host-certificate	EMPTY>
<!ATTLIST host-certificate
	  field		  (ca-list|issuer-name|subject-name|serial-number
			   |extended-key-usage)	#REQUIRED
	  pattern		 CDATA	#IMPLIED
	  pattern-case-sensitive CDATA	#IMPLIED
	  regexp		 CDATA	#IMPLIED
	  ignore-prefix          (yes|no) #IMPLIED
	  ignore-suffix          (yes|no) #IMPLIED
	  explicit		 (yes|no) #IMPLIED
	  allow-undefined 	 (yes|no)

<!-- IP address selector. -->
<!-- The address will be one of the following:				-->
<!--   - an IP range of the form x.x.x.x-y.y.y.y			-->
<!--   - an IP mask of the form x.x.x.x/y				-->
<!--   - a straight IP address x.x.x.x					-->
<!--   - an FQDN pattern (form not checked, either it matches or not) 	-->
<!-- Exactly one of address or fqdn must be set. -->
	  address		CDATA	#IMPLIED
	  fqdn			CDATA	#IMPLIED
	  fqdn-regexp		CDATA	#IMPLIED
	  allow-undefined 	(yes|no)

<!-- User name selector. -->
<!ATTLIST user
	  name			CDATA	#IMPLIED
	  name-case-sensitive	CDATA	#IMPLIED
	  name-regexp		CDATA	#IMPLIED
	  allow-undefined 	(yes|no)

<!-- User group selector. -->
<!ELEMENT user-group		EMPTY>
<!ATTLIST user-group
	  name			CDATA	#IMPLIED
	  name-case-sensitive	CDATA	#IMPLIED
	  name-regexp		CDATA	#IMPLIED
	  allow-undefined 	(yes|no)

<!-- User privileged (administrator) selector. -->
<!ELEMENT user-privileged	EMPTY>
<!ATTLIST user-privileged
	  value 		(yes|no)
	  allow-undefined 	(yes|no)

<!-- Selector for the need of user password change. -->
<!ELEMENT user-password-change-needed	EMPTY>
<!ATTLIST user-password-change-needed
	  value 		(yes|no)
	  allow-undefined 	(yes|no)

<!-- Blackboard selector. -->
<!ELEMENT blackboard		EMPTY>
<!ATTLIST blackboard
	  field				CDATA	#REQUIRED
	  pattern			CDATA	#IMPLIED
	  pattern-case-sensitive	CDATA	#IMPLIED
	  regexp		 	CDATA	#IMPLIED
	  allow-undefined 		(yes|no)

<!-- Authentication methods element. -->
<!ELEMENT authentication-methods	(banner-message?,auth-file-modes?
<!ATTLIST authentication-methods
	  login-grace-time	CDATA	"&default-login-grace-time-seconds;">

<!-- Banner message element. -->
<!ELEMENT banner-message	(#PCDATA)>
<!ATTLIST banner-message
	  file		CDATA	#IMPLIED>

<!-- Authentication file permission checks. -->
<!ELEMENT auth-file-modes	EMPTY>
<!ATTLIST auth-file-modes
	  strict		(yes|no)	"&default-strict-modes;"
	  mask-bits		CDATA		"&default-mask-bits;"
          dir-mask-bits         CDATA           #IMPLIED>

<!-- Authentication element.  In an authentication element, different -->
<!-- authentication methods are in OR-relation.	 User must pass one of -->
<!-- them. -->
<!ELEMENT authentication	(selector*
<!ATTLIST authentication
	  name		ID		#IMPLIED
	  action	(allow|deny)	"&default-authentication-action;"
	  set-group	CDATA		#IMPLIED
          repeat-block  (yes|no)        "no">

<!ELEMENT set-user	EMPTY>
<!ATTLIST set-user
	  name		CDATA		#REQUIRED>

<!ATTLIST mapper
          command	CDATA		#REQUIRED>

<!ELEMENT login-restrictions EMPTY>
<!ATTLIST login-restrictions
	  ignore-password-expiration    CDATA #IMPLIED
	  ignore-aix-rlogin	        CDATA #IMPLIED
	  ignore-aix-login	        CDATA #IMPLIED
	  ignore-nisplus-no-permission  CDATA #IMPLIED>

<!ELEMENT set-blackboard	(#PCDATA)>
<!ATTLIST set-blackboard
	  field		CDATA		#REQUIRED
          value         CDATA           #IMPLIED
          file          CDATA           #IMPLIED>

<!-- Public-key authentication. -->
<!ELEMENT auth-publickey	EMPTY>
<!ATTLIST auth-publickey
          require-dns-match             (yes|no)
	  signature-algorithms           CDATA   #IMPLIED
          authorization-file             CDATA   #IMPLIED
          authorized-keys-directory      CDATA   #IMPLIED
          openssh-authorized-keys-file   CDATA   #IMPLIED
	  allow-missing 		 (yes|no)

<!-- Host-based authentication. -->
<!ELEMENT auth-hostbased	EMPTY>
<!ATTLIST auth-hostbased
	  require-dns-match	(yes|no)
	  disable-authorization	(yes|no) "no"
	  allow-missing 	(yes|no)

<!-- Password authentication. -->
<!ELEMENT auth-password		EMPTY>
<!ATTLIST auth-password
	  failure-delay		CDATA "&default-auth-password-failure-delay;"
	  max-tries		CDATA "&default-auth-password-max-tries;"
	  allow-missing 	(yes|no)

<!-- Keyboard-interactive authentication. -->
<!ELEMENT auth-keyboard-interactive	((submethod-pam

<!ATTLIST auth-keyboard-interactive
	  failure-delay		CDATA "&default-auth-kbdint-failure-delay;"
	  max-tries		CDATA "&default-auth-kbdint-max-tries;">

<!-- Keyboard-interactive submethods. -->

<!-- PAM. service-name is #IMPLIED, as it will be by default whatever is -->
<!-- set in "params" block.                                              -->
<!ELEMENT submethod-pam		EMPTY>
<!ATTLIST submethod-pam
	  service-name		CDATA	#IMPLIED
	  dll-path		CDATA	#IMPLIED>

<!-- Password. -->
<!ELEMENT submethod-password	EMPTY>

<!-- SecurID. -->
<!ELEMENT submethod-securid	EMPTY>
<!ATTLIST submethod-securid
	  dll-path		CDATA	#IMPLIED>

<!-- RADIUS. -->
<!ELEMENT submethod-radius	(radius-server+)>

<!-- RADIUS server. -->
<!ELEMENT radius-server		(radius-shared-secret)>
<!ATTLIST radius-server
	  address		CDATA	#REQUIRED
	  port			CDATA	"&default-radius-server-port;"
	  timeout		CDATA	"&default-radius-server-timeout;"
	  client-nas-identifier CDATA	#IMPLIED>

<!-- Secret. "file" has precedence over #PCDATA. -->
<!ELEMENT radius-shared-secret	(#PCDATA)>
<!ATTLIST radius-shared-secret
	  file			CDATA	#IMPLIED>

<!-- AIX LAM. -->
<!ELEMENT submethod-aix-lam	 EMPTY>
<!ATTLIST submethod-aix-lam
	  enable-password-change (yes|no) "&default-aix-lam-password-change;">

<!-- Generic submethod. -->
<!ELEMENT submethod-generic	EMPTY>
<!ATTLIST submethod-generic
	  params		CDATA	#IMPLIED>

<!-- GSSAPI authentication. -->
<!ELEMENT auth-gssapi	EMPTY>
<!ATTLIST auth-gssapi
	  dll-path		      CDATA	#IMPLIED
	  allow-ticket-forwarding     (yes|no)
	  allow-missing 	      (yes|no)

<!ELEMENT auth-none	EMPTY>
<!ATTLIST auth-none
	  allow-missing 	      (yes|no)

<!-- Services element. -->
<!ELEMENT services	(group*,rule+)>

<!-- Group element. -->
<!ELEMENT group		(selector+)>
<!ATTLIST group
	  name	ID	#REQUIRED>

<!-- Rule element. Maximum one of each of "terminal", "tunnel-agent"    -->
<!-- or "tunnel-x11" can be present.                                    -->
<!ELEMENT rule		(environment|terminal|subsystem|command

<!-- "group", if defined, will be used to match the rule. -->
<!ATTLIST rule
	  group		CDATA		#IMPLIED
	  idle-timeout	CDATA		"&default-idle-timeout;"
	  print-motd	(yes|no)	"&default-print-motd;">

<!-- Environment. -->
<!-- The default allowed environment variables are:	       -->
<!-- allowed-case-sensitive="TERM,PATH,TZ,LANG,LC_*"	       -->
<!-- If neither allowed nor allowed-case-sensitive is set,     -->
<!-- the default is used.				       -->
<!ELEMENT environment	EMPTY>
<!ATTLIST environment
	  allowed			CDATA	#IMPLIED
	  allowed-case-sensitive	CDATA	#IMPLIED>

<!-- Terminal. -->
<!ELEMENT terminal	EMPTY>
<!ATTLIST terminal
	  action	(allow|deny)		"&default-terminal-action;"
	  chroot	CDATA			#IMPLIED>

<!-- Subsystem. -->
<!ELEMENT subsystem	(attribute*)>
<!ATTLIST subsystem
	  action	(allow|deny)	"&default-subsystem-action;"
	  audit	        (yes|no)	"&default-subsystem-audit;"
	  exec-directly CDATA   #IMPLIED
	  application	CDATA		#IMPLIED
	  chroot	CDATA		#IMPLIED>

<!ELEMENT attribute	EMPTY>
<!ATTLIST attribute
	  value		CDATA	#IMPLIED>

<!-- Tunnels. -->

<!ELEMENT tunnel-x11	EMPTY>
<!ATTLIST tunnel-x11
	  action	(allow|deny)		"&default-tunnel-action;">

<!ELEMENT tunnel-agent	EMPTY>
<!ATTLIST tunnel-agent
	  action	(allow|deny)		"&default-tunnel-action;">

<!ELEMENT tunnel-local	((src|dst)*)>
<!ATTLIST tunnel-local
	  action	(allow|deny)		"&default-tunnel-action;">

<!ELEMENT tunnel-remote ((src|listen)*)>
<!ATTLIST tunnel-remote
	  action	(allow|deny)		"&default-tunnel-action;">

<!-- Tunnel selectors. These apply only to TCP local and remote tunnels.-->
<!-- src and dst are for local-tcp 					-->
<!-- src and listen are for remote-tcp 					-->

<!-- address or fqdn are not mandatory. If set, exactly one must be set -->
<!-- (not both).							-->

<!-- Source. -->
	  address	CDATA	#IMPLIED
	  fqdn-regexp	CDATA	#IMPLIED
	  port		CDATA	#IMPLIED>

<!-- Destination. -->
	  address	CDATA	#IMPLIED
	  fqdn-regexp	CDATA	#IMPLIED
	  port		CDATA	#IMPLIED>

<!-- Listener. -->
<!ATTLIST listen
	  address	CDATA	#IMPLIED
	  port		CDATA	#IMPLIED>

<!-- Command. -->
<!ELEMENT command			EMPTY>
<!ATTLIST command
	  action			(allow|deny|forced)
	  interactive           (yes|no) 
	  application			CDATA	#IMPLIED
	  application-case-sensitive	CDATA	#IMPLIED
	  chroot			CDATA	#IMPLIED>




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