HP OpenVMS Systems Documentation

Time parameters allow you to change information about network time services available to clients on the network.

Network Time Protocol (NTP) Servers

Specifies a list of RFC 1305 time servers available to the client. List the server addresses in the order of preference.

Use this format: ddd.ddd.ddd.ddd.

X parameters configure X11-related parameters on a per-host basis.

X Window Display Manager

Specifies a list of IP addresses of systems that are running the X Window System display manager and that are available to the client.

Enter IP addresses in the order of preference.

Use this format: ddd.ddd.ddd.ddd.

X Window Font Server

Specifies a list of X Window System font servers available to the client. Enter the server addresses in the order of preference.

Use this format: ddd.ddd.ddd.ddd.

After you convert your existing BOOTP file to the new DHCPCAP. file as described in Section 8.4.1, you are ready to begin serving your existing BOOTP clients without any further changes.

This section explains how to use the GUI to configure static IP addressing for any DHCP/BOOTP clients you add in the future, as appropriate.

Configuring static IP addressing for DHCP and BOOTP client requires different steps described in the following sections.

8.6.1 Static IP Addressing for BOOTP Clients

To define static IP addressing, specify a specific IP address for a specific MAC address as follows:

1. Start the GUI by entering the following command:

   $ DHCPGUI

2. Click the Nodes tab.
3. Choose [New Record].
4. Enter the host name (Name).
5. Enter the MAC/hardware address. For example, 08:00:20:3f:12:4b.
6. Choose Hardware Type from Key Parameters. Enter the type of network on which the node resides. Enter the hardware type using the symbol or the type number as shown in Table 8-6.
7. Choose [Host IP Address].
8. Enter the Host IP address of the host computer for this node.
9. As appropriate, enter information for Network, Lease, Time, BOOTP, NetBIOS, X Window, TCP, IP, and Link parameters. For more information about these parameters, refer to Section 8.5.3.4.
10. Choose Update from the File menu to update the server with the new configuration.

Select static addressing if you want to assign a specific IP address with a permanent lease time to a DHCP client, and you do not want the client to be able to release this IP address. Also, select static addressing if you need to select an IP address that is not part of any IP address pool.

Selecting an IP address from outside an IP address pool allows the server to specify a permanent mapping between a DHCP client's MAC address and the desired IP address. A client can reuse and release any address within an IP pool.

To configure a specific, permanent address for a DHCP client, do the following:

1. Start the GUI by entering the following command:

   $ DHCPGUI

2. Click the Server/Security tab.
3. Choose Active IP Snapshot, then choose [New Record].
4. Enter the MAC address.
5. Enter the MAC type.
6. Enter the MAC address length.
7. Enter an IP address that does not belong to any IP address pools.
8. Enter -1 (infinite lease) for the lease expiration.
9. Enter the server IP address.
10. If you want a name associated with the client, specify the client's host name and domain name.

If you set the Use MAC addr as Client ID parameter to True, the server uses the MAC address to uniquely identify the clients. The MAC address field might not be the actual MAC address of the client's network adapter. Clients that modify the structure of the MAC address before sending it to the server include:

• Windows 95, Windows NT, and Windows for Workgroups 3.11 with Microsoft TCP/IP
  On these platforms, the MAC address is prefixed with the hardware type. The MAC type is 0 and the length is 7 (instead of 6). For example, if your Ethernet address is 11:22:33:44:55:66, you need to specify the following for the static IP mapping:
  • MAC Address: 01:11:22:33:44:55:66
  • MAC Type: 0
  • MAC length: 7
• FTP Software's OnNet client
  On this platform, the string "cid-" prefixes the MAC address. The MAC type is 0 and the length is 16. For example, if your Ethernet address is 11:22:33:44:55:66, you need to specify the following for the static IP mapping:
  • MAC Address: cid-112233445566
  • MAC Type: 0
  • MAC length: 16

After you run the TCPIP$CONFIG.COM procedure and enable the DHCP server on your system, you can manually define the following client information on a case-by-case basis:

• Static, dynamic, or finite addressing
• Other identifying parameters, such as default gateways and DNS domain names

Defining client addressing and additional parameters manually involves the following steps:

1. Modify the appropriate text-based configuration files.
   These files are listed in Section 8.2.2.
   You manually edit the DHCP configuration files using a text editor such as EDT, TPU, or LSE. Depending on your environment, you may or may not need to modify all the files.
2. If appropriate, run DHCP utilities to update the binary databases.
   When you are modifying information already stored in the databases, you use command line utilities to access and update the database contents. These utilities are defined as both OpenVMS and UNIX commands. Table 8-10 lists the utilities.
3. Reinitialize the DHCP server for the changes to take effect (see Section 8.7.3).

The DHCPCAP. file describes the various configuration parameters for the clients. This file is similar to the standard bootptab file used by most BOOTP servers. Each entry in the file can describe a single machine (per-node basis) or all the machines within a subnet (per-subnet basis) or a group of machines (per-group basis).

8.7.2.1 DHCPCAP Configuration Syntax

The DHCPCAP. configuration file uses two-character, case-sensitive symbols that represent host parameters. Colons (:) follow and separate parameters from one another. For example, gw specifies gateway. For a list of the available symbols, see Section 8.7.2.5.

The following is the format of a configuration file entry:

entryname:symbol=value:symbol=value:symbol=value:

In this format:

• entryname is usually the name of the BOOTP or DHCP client.
• symbol is the two-character symbol that describes the parameters to be associated with the client.
• value is a valid entry that represents the symbol. For more information, see Section 8.7.2.4.

Example 8-8 shows a sample DHCPCAP file entry.

mypc:\
    :ht=ether:\
    :ha=112233445566:\
    :ip=143.32.3.10:\
    :gw=143.32.3.1:\
    :dn=acme.com:

When you create the DHCPCAP file, entries must conform to the following rules:

• Start each new host entry on a new line. You can make a single entry span multiple lines by ending each line with a backslash (\).
• Terminate each entry name and each symbol/value pair with a colon (:). For readability, you can leave blank spaces between symbol/value pairs.
• Enter the entry name in the first field in the configuration file entry.
• Make sure that the host hardware type ( ht ) precedes the host hardware address ( ha ).

You can delete symbol values associated with a particular client by entering an at sign (@) immediately following the symbol. For example, gw@.

Both BOOTP and DHCP interpret lines that begin with any of the following as comments:

• The pound sign (#)
• One or more blank spaces followed by #
• A blank line

Example 8-9 shows a sample single-host DHCPCAP. file entry. This entry, mypc , describes the configuration for a BOOTP client. It describes the client itself, its IP address, the default gateway, and the domain name.

mypc:\
    :ht=ether:\
    :ha=112233445566:\
    :ip=143.32.3.10:\
    :gw=143.32.3.1:\
    :dn=acme.com:

Example 8-10 shows a subnet DHCPCAP. file entry. This entry, subnet5, describes the parameters for all the clients on a particular subnet, 143.32.5.0. It describes the default gateway, subnet mask, domain name, DNS server address, and lease time of the address.

subnet5:\
       :nw=143.32.5.0:\
       :gw=143.32.5.1:\
       :sm=255.255.255.0:\
       :dn=engr.acme.com:\
       :ds=143.32.5.10:\
       :lt=3600:

The symbol values require specific formats. Use only the following formats:

• ASCII string
  Enclose this string in quotation marks ("string") if it contains any of the special characters: colon (:), pound sign (#), tab, or space.
• ASCII integer list
  A list of integers separated by white space consisting of ASCII-format characters that represent an unsigned hexadecimal, octal, or decimal integer.
  • Begin the string with 0X or 0x if this is a hexadecimal integer.
  • Begin the string with zero (0) if this is an octal integer.
• IP address list
  ASCII string representing an IP address in dotted-decimal notation (for example, 128.119.95.2).
  An IP address list is a string of one or more IP addresses, with the addresses separated by spaces. For example:

  tg=128.119.91.2 128.119.95.42 128.119.95.8

  
  You can also use IP address lists to define DHCP address ranges, routing policy filters, and static routes.
• ASCII-format representation of a hexadecimal integer that DHCP and BOOTP interpret as a hardware address.
  The ASCII string must have the correct number of digits for the specified hardware type; for example, twelve digits for a 48-bit Ethernet address. To improve readability, you can:
  • Separate the two-digit sequences (bytes) with hyphens (-).
  • Separate the two-digit sequences (bytes) with periods (.).
  • Add a 0x prefix to each byte (or only some bytes) of the address.
  • Add a hyphen between some bytes and 0x prefixes before others.
  • Add a period between some bytes and 0x prefixes before others.
  
  Examples of valid hexadecimal ASCII strings are:

  ha=7F-FF-81-00-0A-47 ha=0X7F0XFF0X81000A47 ha=0X7F-FF0XF8-1000A47

• Booleans and switches
  A boolean symbol performs a function just by its presence. A switch is the value 0 or 1, and it associates one of two functions to those values (usually, disable and enable, respectively).

  :hn:\ #This is an example of a boolean type field :ms=1:\ #This is an example of a switch type field

Table 8-8 describes each DHCP configuration file symbol and indicates whether you use the symbol in DHCP configuration only or in BOOTP and DHCP configuration.