calmsacibis995
171 lines
5.6 KiB
Plaintext
171 lines
5.6 KiB
Plaintext
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LDAP configuration file (/var/dhcp/config/dhcp_ldap.conf)
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----------------------------------------------------------
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schema DEN
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This directive indicates that the particular (in this case DEN
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based) schema is used. The search, modify, add, and delete
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directives will differ depending on the schema. The attributes
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under schema are config, subnet_refresh, range_refresh, leases,
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logldif, and online_leases. These are discussed below.
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config files|files&ldap
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This attribute indicates whether only the text files in the
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/var/dhcp/config directory should be used to setup the DHCP
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server configuration for subnets or whether the configuration
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values in the the /var/dhcp/config directory should be
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overwritten by values that are redefined by the configuration in
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the ldap database. By default the files are overwritten by values
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found in the LDAP database if this attribute is not specified.
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subnet_refresh <number>
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This indicates the frequency of subnet configuration refresh. 0
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indicates that the configuration will be loaded only once. The
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configuration is re-read only when the DHCP server is idle. The
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frequency indicates the number of times the server can be idle
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before it will reread the configuration from the ldap
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database. By default the configuration is read in only once at
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startup.
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range_refresh <number>
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This behaves in a similar way to the subnet_refresh.
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leases 0|1
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This indicates whether the leases should be stored in the ldap
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database or not. If the value is 1 leases are updated into an
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LDAP database or logged locally in an ldif file depending on the
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value of the online_leases option described below. By default
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leases are not stored or logged into an ldif file.
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online_leases 0|1
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If this option is specified as 0 leases are not updated
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online. The default value is 1. If the server should log leases
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in a local ldif file for offline updates the user must specify
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the logldif option also.
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logldif [ <filename> ]
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This indicates that LDAP-database-updates of leases should be
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logged to a local ldif file. The default filename used for
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logging is /var/dhcp/ldap_dhcp_log.ldif. A different filename can
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be specified. Note that it is possible to specify both online
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updates as well as logging to an ldif file, or only one of those,
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or neither. Ldif records that can be input to the ldapmodify(3)
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utility are created. It is the responsibility of the user to set
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up an offline update procedure. Note that ldif records are
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appended to the logfile and must be deleted periodically. This
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may be partly or fully automated in later releases.
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server hostip:[port]
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This specifies the ldap server IP address and port (default
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389). Attributes include base, scope, binddn, bindpwd.
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base
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Defines the distinguished name (dn) of the base for the ldap
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search.
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scope
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Defines the depth used in searching for ldap entries. The value
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may be one of the following: subtree - will search all entries
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below the base (default), onelevel - will search one level below
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base, and sbase - will search only at the base level.
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binddn
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Specifies the distinguished name used in binding to the
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server. This attribute is optional.
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bindpwd
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Specifies the password used in binding to the server. This
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attribute is also optional.
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entry search <entry_name>
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entry modify <entry_name>
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entry add <entry_name>
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entry delete <entry_name>
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The search specification is similar to the table specification in
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ldap.conf(4). In addition the search specification will allow to
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override the base and scope specified in the server
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specification. The base can also be modified on the fly with
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substitutions similar to substitutions in the "format" specification.
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For example:
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entry search subnets
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base DHCPService=%s, o=sgi.com
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scope sub
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filter_lookup
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filter_list
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getattr
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setattr
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require
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A comparison with the man page for ldap.conf(4) indicates that
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the "single line" and the "default" keywords are dropped since
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they are not needed. The "format" keyword is replaced by the
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"getattr" keyword which simply specifies a list of attributes
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separated by [,: \t]. The attributes values are returned either
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as strings or as binary values in "struct berval" format depending
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on the specification of the "=B" modifier. For example
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getattr DHCPSubnets, DHCPOptionsList=B
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will get the DHCPOptionsList as a binary value.
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Note that with the DEN based schema used at present, all
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attributes are string values.
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NOTES ABOUT LDAP SERVER USAGE.
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-------------------------------
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The DHCP Server should be able to run without the ldap database
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also. Therefore basic internal data structures that are used are
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the same regardless of whether LDAP updates are specified or not.
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To improve the performance of searches the DHCP server continues
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to store leases in a local ndbm file. Lease queries are made only
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locally. Only lease updates are sent to a (remote) LDAP server if
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online updating is specified. This has the added advantage that
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if the LDAP server is down, online updates can be suspended for
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some time an instead the updates can be logged to a local ldif
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file. The DHCP service can continue uninterrupted because the
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ndbm database is local and is always current.
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An Example of entries in the configuration file.
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------------------------------------------------
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Suppose the DHCP server wants to know what subnets are to be
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supported so that it can build the necessary "Config" structures.
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For the DEN library the search entry will be:
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entry search SUBNETS
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filter_lookup (|(objectclass=DHCPService)(objectclass=DHCPServer))
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require DHCPSubnetList
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getattr DHCPSubnetList
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An example configuration file is in /var/dhcp/config/dhcp_ldap.conf.
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