Description
Tellurian DhcpdNT is configured by editing a simple text file. You specify the name of that text file with the -c option when you start the service. By default the configuration is stored in the file, C:\dhcpd.conf.The dhcpd.conf file is a free-form ASCII text file. It is parsed by the recursive-descent parser built into DhcpdNT. The file may contain extra tabs and newlines for formatting purposes. Keywords in the file are case-insensitive. Comments may be placed anywhere within the file (except within quotes). Comments begin with the # character and end at the end of the line.
The file essentially consists of a list of statements. Statements fall into two broad categories - parameters and declarations.
Parameter statements either say how to do something (e.g., how long a lease to offer), whether to do something (e.g., should DhcpdNT provide addresses to unknown clients), or what parameters to provide to the client (e.g., use gateway 220.177.244.7).
Declarations are used to describe the topology of the network, to describe clients on the network, to provide addresses that can be assigned to clients, or to apply a group of parameters to a group of declarations. In any group of parameters and declarations, all parameters must be specified before any declarations which depend on those parameters may be specified.
Declarations about network topology include the shared-network and the subnet declarations. If clients on a subnet are to be assigned addresses dynamically, a range declaration must appear within the subnet declaration. For clients with statically assigned addresses, or for installations where only known clients will be served, each such client must have a host declaration. If parameters are to be applied to a group of declarations which are not related strictly on a per-subnet basis, the group declaration can be used.
For every subnet which will be served, and for every subnet to which the dhcp server is connected, there must be one subnet declaration, which tells DhcpdNT how to recognize that an address is on that subnet. A subnet declaration is required for each subnet even if no addresses will be dynamically allocated on that subnet.
Some installations have physical networks on which more than one IP subnet operates. For example, if there is a site-wide requirement that 8-bit subnet masks be used, but a department with a single physical ethernet network expands to the point where it has more than 254 nodes, it may be necessary to run two 8-bit subnets on the same ethernet until such time as a new physical network can be added. In this case, the subnet declarations for these two networks may be enclosed in a shared-network declaration.
Some sites may have departments which have clients on more than one subnet, but it may be desirable to offer those clients a uniform set of parameters which are different than what would be offered to clients from other departments on the same subnet. For clients which will be declared explicitly with host declarations, these declarations can be enclosed in a group declaration along with the parameters which are common to that department. For clients whose addresses will be dynamically assigned, there is currently no way to group parameter assignments other than by network topology.
When a client is to be booted, its boot parameters are determined by first consulting that client's host declaration (if any), then consulting the group declaration (if any) which enclosed that host declaration, then consulting the subnet declaration for the subnet on which the client is booting, then consulting the shared-network declaration (if any) containing that subnet, and finally consulting the top-level parameters which may be specified outside of any declaration.
When DhcpdNT tries to find a host declaration for a client, it first looks for a host declaration which has a fixed-address parameter which matches the subnet or shared network on which the client is booting. If it doesn't find any such entry, it then tries to find an entry which has no fixed-address parameter. If no such entry is found, then DhcpdNT acts as if there is no entry in the dhcpd.conf file for that client, even if there is an entry for that client on a different subnet or shared network.
Examples
A typical dhcpd.conf file will look something like this:
global parameters...
shared-network ISC-BIGGIE {
shared-network-specific parameters...
subnet 204.254.239.0 netmask 255.255.255.224 {
subnet-specific parameters...
range 204.254.239.10 204.254.239.30;
}
subnet 204.254.239.32 netmask 255.255.255.224 {
subnet-specific parameters...
range 204.254.239.42 204.254.239.62;
}
}
subnet 204.254.239.64 netmask 255.255.255.224 {
subnet-specific parameters...
range 204.254.239.74 204.254.239.94;
}
group {
group-specific parameters...
host zappo.test.isc.org {
host-specific parameters...
}
host beppo.test.isc.org {
host-specific parameters...
}
host harpo.test.isc.org {
host-specific parameters...
}
}
Notice that at the beginning of the file, there's a place for global parameters. These might be things like the organization's domain name, the addresses of the name servers (if they are common to the entire organization), and so on. So, for example:
option domain-name "isc.org"; option domain-name-servers ns1.isc.org, ns2.isc.org;
As you can see in Figure 2, it's legal to specify host addresses in parameters as domain names rather than as numeric IP addresses. If a given hostname resolves to more than one IP address (for example, if that host has two ethernet interfaces), both addresses are supplied to the client.
In Figure 1, you can see that both the shared-network statement and the subnet statements can have parameters. Let us say that the shared network ISC-BIGGIE supports an entire department - perhaps the accounting department. If accounting has its own domain, then a shared-network-specific parameter might be:
option domain-name "accounting.isc.org";
All subnet declarations appearing in the shared-network declaration would then have the domain-name option set to "accounting.isc.org" instead of just "isc.org".
The most obvious reason for having subnet-specific parameters as shown in Figure 1 is that each subnet, of necessity, has its own router. So for the first subnet, for example, there should be something like:
option routers 204.254.239.1;
Note that the address here is specified numerically. This is not required - if you have a different domain name for each interface on your router, it's perfectly legitimate to use the domain name for that interface instead of the numeric address. However, in many cases there may be only one domain name for all of a router's IP addresses, and it would not be appropriate to use that name here.
In Figure 1 there is also a group statement, which provides common parameters for a set of three hosts - zappo, beppo and harpo. As you can see, these hosts are all in the test.isc.org domain, so it might make sense for a group-specific parameter to override the domain name supplied to these hosts:
option domain-name "test.isc.org";
Also, given the domain they're in, these are probably test machines. If we wanted to test the DHCP leasing mechanism, we might set the lease timeout somewhat shorter than the default:
max-lease-time 120; default-lease-time 120;
You may have noticed that while some parameters start with the option keyword, some do not. Parameters starting with the option keyword correspond to actual DHCP options, while parameters that do not start with the option keyword either control the behaviour of the DHCP server (e.g., how long a lease DhcpdNT will give out), or specify client parameters that are not optional in the DHCP protocol (for example, server-name and filename).
In Figure 1, each host had host-specific parameters. These could include such things as the hostname option, the name of a file to upload (the filename parameter) and the address of the server from which to upload the file (the next-server parameter). In general, any parameter can appear anywhere that parameters are allowed, and will be applied according to the scope in which the parameter appears.
Imagine that you have a site with a lot of NCD X-Terminals. These terminals come in a variety of models, and you want to specify the boot files for each models. One way to do this would be to have host declarations for each server and group them by model:
group {
filename "Xncd19r";
next-server ncd-booter;
host ncd1 { hardware ethernet 0:c0:c3:49:2b:57; }
host ncd4 { hardware ethernet 0:c0:c3:80:fc:32; }
host ncd8 { hardware ethernet 0:c0:c3:22:46:81; }
}
group {
filename "Xncd19c";
next-server ncd-booter;
host ncd2 { hardware ethernet 0:c0:c3:88:2d:81; }
host ncd3 { hardware ethernet 0:c0:c3:00:14:11; }
}
group {
filename "XncdHMX";
next-server ncd-booter;
host ncd1 { hardware ethernet 0:c0:c3:11:90:23; }
host ncd4 { hardware ethernet 0:c0:c3:91:a7:8; }
host ncd8 { hardware ethernet 0:c0:c3:cc:a:8f; }
}
Reference: Declarations
The shared-network statement
shared-network name {
[ parameters ]
[ declarations ]
}
The shared-network statement is used to inform the DHCP server that some IP subnets actually share the same physical network. Any subnets in a shared network should be declared within a shared-network statement. Parameters specified in the shared-network statement will be used when booting clients on those subnets unless parameters provided at the subnet or host level override them. If any subnet in a shared network has addresses available for dynamic allocation, those addresses are collected into a common pool for that shared network and assigned to clients as needed. There is no way to distinguish on which subnet of a shared network a client should boot.
Name should be the name of the shared network. This name is used when printing debugging messages, so it should be descriptive for the shared network. The name may have the syntax of a valid domain name (although it will never be used as such), or it may be any arbitrary name, enclosed in quotes.
The subnet statement
subnet subnet-number netmask netmask {
[ parameters ]
[ declarations ]
}
The subnet statement is used to provide DhcpdNT with enough information to tell whether or not an IP address is on that subnet. It may also be used to provide subnet-specific parameters and to specify what addresses may be dynamically allocated to clients booting on that subnet. Such addresses are specified using the range declaration.
The subnet-number should be an IP address or domain name which resolves to the subnet number of the subnet being described. The netmask should be an IP address or domain name which resolves to the subnet mask of the subnet being described. The subnet number, together with the netmask, are sufficient to determine whether any given IP address is on the specified subnet.
Although a netmask must be given with every subnet declaration, it is recommended that if there is any variance in subnet masks at a site, a subnet-mask option statement be used in each subnet declaration to set the desired subnet mask, since any subnet-mask option statement will override the subnet mask declared in the subnet statement.
The range statement
range [ dynamic-bootp ] low-address [ high-address];
For any subnet on which addresses will be assigned dynamically, there must be at least one range statement. The range statement gives the lowest and highest IP addresses in a range. All IP addresses in the range should be in the subnet in which the range statement is declared. The dynamic-bootp flag may be specified if addresses in the specified range may be dynamically assigned to BOOTP clients as well as DHCP clients. When specifying a single address, high-address can be omitted.
The host statement
host hostname {
[ parameters ]
[ declarations ]
}
There must be at least one host statement for every BOOTP client that is to be served. host statements may also be specified for DHCP clients, although this is not required unless booting is only enabled for known hosts.
If it is desirable to be able to boot a DHCP or BOOTP client on more than one subnet with fixed addresses, more than one address may be specified in the fixed-address parameter, or more than one host statement may be specified.
If client-specific boot parameters must change based on the network to which the client is attached, then multiple host statements should be used.
If a client is to be booted using a fixed address if it's possible, but should be allocated a dynamic address otherwise, then a host statement must be specified without a fixed-address clause. hostname should be a name identifying the host. If a hostname option is not specified for the host, hostname is used.
Host declarations are matched to actual DHCP or BOOTP clients by matching the dhcp-client-identifier option specified in the host declaration to the one supplied by the client, or, if the host declaration or the client does not provide a dhcp-client-identifier option, by matching the hardware parameter in the host declaration to the network hardware address supplied by the client. BOOTP clients do not normally provide a dhcp-client-identifier, so the hardware address must be used for all clients that may boot using the BOOTP protocol.
The group statement
group {
[ parameters ]
[ declarations ]
}
The group statement is used simply to apply one or more parameters to a group of declarations. It can be used to group hosts, shared networks, subnets, or even other groups.
Reference: Allow and Deny
The allow and deny statements can be used to control the behaviour of DhcpdNT to various sorts of requests.
The unknown-clients keyword
allow unknown-clients; deny unknown-clients;The unknown-clients flag is used to tell DhcpdNT whether or not to dynamically assign addresses to unknown clients. Dynamic address assignment to unknown clients is allowed by default.
The bootp keyword
allow bootp; deny bootp;The bootp flag is used to tell DhcpdNT whether or not to respond to bootp queries. Bootp queries are allowed by default.
The booting keyword
allow booting; deny booting;The booting flag is used to tell DhcpdNT whether or not to respond to queries from a particular client. This keyword only has meaning when it appears in a host declaration. By default, booting is allowed, but if it is disabled for a particular client, then that client will not be able to get and address from the DHCP server.
Reference: Parameters
The default-lease-time statement
default-lease-time time;Time should be the length in seconds that will be assigned to a lease if the client requesting the lease does not ask for a specific expiration time.
The max-lease-time statement
max-lease-time time;Time should be the maximum length in seconds that will be assigned to a lease if the client requesting the lease asks for a specific expiration time.
The hardware statement
hardware hardware-type hardware-address;In order for a BOOTP client to be recognized, its network hardware address must be declared using a hardware clause in the host statement. hardware-type must be the name of a physical hardware interface type. Currently, only the ethernet and token-ring types are recognized, although support for a fddi hardware type (and others) would also be desirable. The hardware-address should be a set of hexadecimal octets (numbers from 0 through ff) seperated by colons. The hardware statement may also be used for DHCP clients.
The filename statement
filename "filename";The filename statement can be used to specify the name of the initial boot file which is to be loaded by a client. The filename should be a filename recognizable to whatever file transfer protocol the client can be expected to use to load the file.
The server-name statement
server-name "name";The server-name statement can be used to inform the client of the name of the server from which it is booting. Name should be the name that will be provided to the client.
The next-server statement
next-server server-name;The next-server statement is used to specify the host address of the server from which the initial boot file (specified in the filename statement) is to be loaded. Server-name should be a numeric IP address or a domain name. If no next-server parameter applies to a given client, the DHCP server's IP address is used.
The fixed-address statement
fixed-address address [, address ... ];The fixed-address statement is used to assign one or more fixed IP addresses to a client. It should only appear in a host declaration. If more than one address is supplied, then when the client boots, it will be assigned the address which corresponds to the network on which it is booting. If none of the addresses in the fixed-address statement are on the network on which the client is booting, that client will not match the host declaration containing that fixed-address statement. Each address should be either an IP address or a domain name which resolves to one or more IP addresses.
The dynamic-bootp-lease-cutoff statement
dynamic-bootp-lease-cutoff date;The dynamic-bootp-lease-cutoff statement sets the ending time for all leases assigned dynamically to BOOTP clients. Because BOOTP clients do not have any way of renewing leases, and don't know that their leases could expire, by default DhcpdNT assignes infinite leases to all BOOTP clients. However, it may make sense in some situations to set a cutoff date for all BOOTP leases - for example, the end of a school term, or the time at night when a facility is closed and all machines are required to be powered off.
Date should be the date on which all assigned BOOTP leases will end. The date is specified in the form:
W is the day of the week expressed as a number from zero (Sunday) to six (Saturday). YYYY is the year, including the century. MM is the month expressed as a number from 1 to 12. DD is the day of the month, counting from 1. HH is the hour, from zero to 23. MM is the minute and SS is the second. The time is always in Greenwich Mean Time (GMT), not local time.
The dynamic-bootp-lease-length statement
dynamic-bootp-lease-length length;The dynamic-bootp-lease-length statement is used to set the length of leases dynamically assigned to BOOTP clients. At some sites, it may be possible to assume that a lease is no longer in use if its holder has not used BOOTP or DHCP to get its address within a certain time period. The period is specified in length as a number of seconds. If a client reboots using BOOTP during the timeout period, the lease duration is reset to length, so a BOOTP client that boots frequently enough will never lose its lease. Needless to say, this parameter should be adjusted with extreme caution.
The get-lease-hostnames statement
get-lease-hostnames flag;The get-lease-hostnames statement is used to tell DhcpdNT whether or not to look up the domain name corresponding to the IP address of each address in the lease pool and use that address for the DHCP hostname option. If flag is true, then this lookup is done for all addresses in the current scope. By default, or if flag is false, no lookups are done.
The use-host-decl-names statement
use-host-decl-names flag;If the use-host-decl-names parameter is true in a given scope, then for every host declaration within that scope, the name provided for the host declaration will be supplied to the client as its hostname. So, for example,
group {
use-host-decl-names on;
host joe {
hardware ethernet 08:00:2b:4c:29:32;
fixed-address joe.fugue.com;
}
}
is equivalent to
host joe {
hardware ethernet 08:00:2b:4c:29:32;
fixed-address joe.fugue.com;
option host-name "joe";
}
An option host-name statement within a host declaration will override the use of the name in the host declaration.
The server-identifier statement
server-identifier hostname;The server-identifier statement can be used to define the value that is sent in the DHCP Server Identifier option for a given scope. The value specified must be an IP address for the DHCP server, and must be reachable by all clients served by a particular scope.
The use of the server-identifier statement is not recommended - the only reason to use it is to force a value other than the default value to be sent on occasions where the default value would be incorrect. The default value is the first IP address associated with the physical network interface on which the request arrived. The usual case where the server-identifier statement needs to be sent is when a physical interface has more than one IP address, and the one being sent by default isn't appropriate for some or all clients served by that interface.
Reference: Option Statements
The Dynamic Host Configuration protocol allows the client to receive options from the DHCP server describing the network configuration and various services that are available on the network. When configuring DhcpdNT, options must often be declared. The syntax for declaring options, and the names and formats of the options that can be declared, are documented here.DHCP option statements always start with the option keyword, followed by an option name, followed by option data. The option names and data formats are described below. It is not necessary to exhaustively specify all DHCP options - only those options which are needed by clients must be specified.
Option data comes in a variety of formats, as defined below:
The ip-address data type can be entered either as an explicit IP address (e.g., 239.254.197.10) or as a domain name (e.g., haagen.isc.org). When entering a domain name, be sure that that domain name resolves to a single IP address.
The int32 data type specifies a signed 32-bit integer. The uint32 data type specifies an unsigned 32-bit integer. The int16 and uint16 data types specify signed and unsigned 16-bit integers. The int8 and uint8 data types specify signed and unsigned 8-bit integers. Unsigned 8-bit integers are also sometimes referred to as octets.
The string data type specifies an NVT ASCII string, which must be enclosed in double quotes - for example, to specify a domain-name option, the syntax would be
option domain-name "isc.org";
The flag data type specifies a boolean value. Booleans can be either true or false (or on or off, if that makes more sense to you).
The data-string data type specifies either an NVT ASCII string enclosed in double quotes, or a series of octets specified in hexadecimal, seperated by colons. For example:
option client-identifier "CLIENT-FOO";or
option client-identifier 43:4c:49:45:54:2d:46:4f:4f;
The documentation for the various options mentioned below is taken from the latest IETF draft document on DHCP options. Options which are not listed by name may be defined by the name option-nnn, where nnn is the decimal number of the option code. These options may be followed either by a string, enclosed in quotes, or by a series of octets, expressed as two-digit hexadecimal numbers seperated by colons. For example:
option option-133 "my-option-133-text"; option option-129 1:54:c9:2b:47;Because dhcpd does not know the format of these undefined option codes, no checking is done to ensure the correctness of the entered data.
The standard options are:
option subnet-mask ip-address;The subnet mask option specifies the client's subnet mask as per RFC 950. If no subnet mask option is provided anywhere in scope, as a last resort dhcpd will use the subnet mask from the subnet declaration for the network on which an address is being assigned. However, any subnet-mask option declaration that is in scope for the address being assigned will override the subnet mask specified in the subnet declaration.
option time-offset int32;The time-offset option specifies the offset of the client's subnet in seconds from Coordinated Universal Time (UTC).
option routers ip-address [, ip-address ... ];The routers option specifies a list of IP addresses for routers on the client's subnet. Routers should be listed in order of preference.
option time-servers ip-address [, ip-address ... ];The time-server option specifies a list of RFC 868 time servers available to the client. Servers should be listed in order of preference.
option ien116-name-servers ip-address [, ip-address ... ];The ien116-name-servers option specifies a list of IEN 116 name servers available to the client. Servers should be listed in order of preference.
option domain-name-servers ip-address [, ip-address ... ];The domain-name-servers option specifies a list of Domain Name System (STD 13, RFC 1035) name servers available to the client. Servers should be listed in order of preference.
option log-servers ip-address [, ip-address ... ];The log-server option specifies a list of MIT-LCS UDP log servers available to the client. Servers should be listed in order of preference.
option cookie-servers ip-address [, ip-address ... ];The cookie server option specifies a list of RFC 865 cookie servers available to the client. Servers should be listed in order of preference.
option lpr-servers ip-address [, ip-address ... ];The LPR server option specifies a list of RFC 1179 line printer servers available to the client. Servers should be listed in order of preference.
option impress-servers ip-address [, ip-address ... ];The impress-server option specifies a list of Imagen Impress servers available to the client. Servers should be listed in order of preference.
option resource-location-servers ip-address [, ip-address ... ];This option specifies a list of RFC 887 Resource Location servers available to the client. Servers should be listed in order of preference.
option host-name string;This option specifies the name of the client. The name may or may not be qualified with the local domain name (it is preferable to use the domain-name option to specify the domain name). See RFC 1035 for character set restrictions.
option boot-size uint16;This option specifies the length in 512-octet blocks of the default boot image for the client.
option merit-dump string;This option specifies the path-name of a file to which the client's core image should be dumped in the event the client crashes. The path is formatted as a character string consisting of characters from the NVT ASCII character set.
option domain-name string;This option specifies the domain name that client should use when resolving hostnames via the Domain Name System.
option swap-server ip-address;This specifies the IP address of the client's swap server.
option root-path string;This option specifies the path-name that contains the client's root disk. The path is formatted as a character string consisting of characters from the NVT ASCII character set.
option ip-forwarding flag;This option specifies whether the client should configure its IP layer for packet forwarding. A value of 0 means disable IP forwarding, and a value of 1 means enable IP forwarding.
option non-local-source-routing flag;This option specifies whether the client should configure its IP layer to allow forwarding of datagrams with non-local source routes (see Section 3.3.5 of [4] for a discussion of this topic). A value of 0 means disallow forwarding of such datagrams, and a value of 1 means allow forwarding.
option policy-filter ip-address ip-address [, ip-address ip-address ... ];This option specifies policy filters for non-local source routing. The filters consist of a list of IP addresses and masks which specify destination/mask pairs with which to filter incoming source routes.
Any source routed datagram whose next-hop address does not match one of the filters should be discarded by the client.
See STD 3 (RFC1122) for further information.
option max-dgram-reassembly uint16;This option specifies the maximum size datagram that the client should be prepared to reassemble. The minimum value legal value is 576.
option default-ip-ttl uint8;This option specifies the default time-to-live that the client should use on outgoing datagrams.
option path-mtu-aging-timeout uint32;This option specifies the timeout (in seconds) to use when aging Path MTU values discovered by the mechanism defined in RFC 1191.
option path-mtu-plateau-table uint16 [, uint16 ... ];This option specifies a table of MTU sizes to use when performing Path MTU Discovery as defined in RFC 1191. The table is formatted as a list of 16-bit unsigned integers, ordered from smallest to largest. The minimum MTU value cannot be smaller than 68.
option interface-mtu uint16;This option specifies the MTU to use on this interface. The minimum legal value for the MTU is 68.
option all-subnets-local flag;This option specifies whether or not the client may assume that all subnets of the IP network to which the client is connected use the same MTU as the subnet of that network to which the client is directly connected. A value of 1 indicates that all subnets share the same MTU. A value of 0 means that the client should assume that some subnets of the directly connected network may have smaller MTUs.
option broadcast-address ip-address;This option specifies the broadcast address in use on the client's subnet. Legal values for broadcast addresses are specified in section 3.2.1.3 of STD 3 (RFC1122).
option perform-mask-discovery flag;This option specifies whether or not the client should perform subnet mask discovery using ICMP. A value of 0 indicates that the client should not perform mask discovery. A value of 1 means that the client should perform mask discovery.
option mask-supplier flag;This option specifies whether or not the client should respond to subnet mask requests using ICMP. A value of 0 indicates that the client should not respond. A value of 1 means that the client should respond.
option router-discovery flag;This option specifies whether or not the client should solicit routers using the Router Discovery mechanism defined in RFC 1256. A value of 0 indicates that the client should not perform router discovery. A value of 1 means that the client should perform router discovery.
option router-solicitation-address ip-address;This option specifies the address to which the client should transmit router solicitation requests.
option static-routes ip-address ip-address [, ip-address ip-address ... ];This option specifies a list of static routes that the client should install in its routing cache. If multiple routes to the same destination are specified, they are listed in descending order of priority.
The routes consist of a list of IP address pairs. The first address is the destination address, and the second address is the router for the destination.
The default route (0.0.0.0) is an illegal destination for a static route. To specify the default route, use the routers option.
option trailer-encapsulation flag;This option specifies whether or not the client should negotiate the use of trailers (RFC 893 [14]) when using the ARP protocol. A value of 0 indicates that the client should not attempt to use trailers. A value of 1 means that the client should attempt to use trailers.
option arp-cache-timeout uint32;This option specifies the timeout in seconds for ARP cache entries.
option ieee802-3-encapsulation flag;This option specifies whether or not the client should use Ethernet Version 2 (RFC 894) or IEEE 802.3 (RFC 1042) encapsulation if the interface is an Ethernet. A value of 0 indicates that the client should use RFC 894 encapsulation. A value of 1 means that the client should use RFC 1042 encapsulation.
option default-tcp-ttl uint8;This option specifies the default TTL that the client should use when sending TCP segments. The minimum value is 1.
option tcp-keepalive-interval uint32;This option specifies the interval (in seconds) that the client TCP should wait before sending a keepalive message on a TCP connection. The time is specified as a 32-bit unsigned integer. A value of zero indicates that the client should not generate keepalive messages on connections unless specifically requested by an application.
option tcp-keepalive-garbage flag;This option specifies the whether or not the client should send TCP keepalive messages with a octet of garbage for compatibility with older implementations. A value of 0 indicates that a garbage octet should not be sent. A value of 1 indicates that a garbage octet should be sent.
option nis-domain string;This option specifies the name of the client's NIS (Sun Network Information Services) domain. The domain is formatted as a character string consisting of characters from the NVT ASCII character set.
option nis-servers ip-address [, ip-address ... ];This option specifies a list of IP addresses indicating NIS servers available to the client. Servers should be listed in order of preference.
option ntp-servers ip-address [, ip-address ... ];This option specifies a list of IP addresses indicating NTP (RFC 1035) servers available to the client. Servers should be listed in order of preference.
option netbios-name-servers ip-address [, ip-address ... ];The NetBIOS name server (NBNS) option specifies a list of RFC 1001/1002 NBNS name servers listed in order of preference.
option netbios-dd-server ip-address [, ip-address ... ];The NetBIOS datagram distribution server (NBDD) option specifies a list of RFC 1001/1002 NBDD servers listed in order of preference.
option netbios-node-type uint8;The NetBIOS node type option allows NetBIOS over TCP/IP clients which are configurable to be configured as described in RFC 1001/1002. The value is specified as a single octet which identifies the client type. A value of 1 corresponds to a NetBIOS B-node; a value of 2 corresponds to a P-node; a value of 4 corresponds to an M-node; a value of 8 corresponds to an H-node.
option netbios-scope string;The NetBIOS scope option specifies the NetBIOS over TCP/IP scope parameter for the client as specified in RFC 1001/1002. See RFC1001, RFC1002, and RFC1035 for character-set restrictions.
option font-servers ip-address [, ip-address ... ];This option specifies a list of X Window System Font servers available to the client. Servers should be listed in order of preference.
option x-display-manager ip-address [, ip-address ... ];This option specifies a list of systems that are running the X Window System Display Manager and are available to the client. Addresses should be listed in order of preference.
option dhcp-client-identifier data-string;This option can be used to specify the a DHCP client identifier in a host declaration, so that dhcpd can find the host record by matching against the client identifier.
See Also
Tellurian DhcpdNT Operation Manual, Tellurian DhcpdNT Error Messages, Tellurian DhcpdNT Leases, RFC2132, RFC2131 and RFC951.Author
DhcpdNT was derived from dhcpd, which was written by Ted Lemon <mellon@vix.com> under a contract with Vixie Labs. Funding for this project was provided by the Internet Software Corporation. Information about the Internet Software Consortium can be found at http://www.isc.org/isc.Conversion of dhcpd to run under Windows was done by Serguei Rossomakhine from Tellurian Pty Ltd. Conversion of the manual pages to HTML was done by David Newall <davidn@tellurian.com.au> from Tellurian. Information about Tellurian can be found at http://www.tellurian.com.au