# Compaq TCP/IP Services for OpenVMS
Management

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### 7.5.2.2 Configuring IP Ranges

Use the IP Ranges parameters to specify the IP addresses that are available to assign to clients.

Note If your network contains subnets, that information must be included in the NETMASKS. file. See Section 7.2.2.4 for more information on the use of netmasks when you are using subnet addressing.

To configure the server IP ranges:

1. Click the Server/Security tab.
2. Choose IP Ranges from the drop-down list.
3. Choose [New IP Range].
4. For each IP range, enter the subnet address or name, a server address, and an IP range to be assigned to clients on the selected subnets.

IP Range Parameters

You can change any or all of the IP range parameters described in this section.

> ### Subnet Address

> Enter the subnet address or name.

> ### DHCP Server (address)

> Enter the IP address or the name of the Server. For cluster failover configurations, enter `0.0.0.0` for the IP address.

> ### IP Ranges

> The IP Address Range is a group of unique IP addresses that the server can assign to clients on a selected subnet. To assign an IP Address Range to a subnet:
> 1. Enter the beginning of the IP Address Range for the subnet: network, subnet, and host address.
> 2. Enter the end of the IP Address Range.
> 3. If your network has more than one subnet, enter the remaining subnet IP numbers.

> Note A subnet address can have more than one corresponding IP Address Range.

> The server can configure clients on more than one subnet when the routers between the server and the client forward BOOTP packets.

### 7.5.2.3 Configuring Host Names

Use the Host Names Lists Parameters to configure a host name. If you have set the server configuration so that the server automatically accepts the name a client suggests for itself or you have added A and PTR records for the hosts to your DNS/BIND database, you do not need to set up host names.

Note Follow the instructions in this section only if the Accept Client Name parameter is set to False.

To configure a host name:

1. Click the Server/Security tab.
2. Choose Host Name Lists from the drop-down list.
3. Choose [New Host name List].
4. For each host name, enter:
   - Domain name
   - DHCP server name
   - Host name Prefix (required as part of the host name)
   - Host names

#### 7.5.2.3.1 Host Name List Parameters

You can use the following host name list parameters to set up host names.

> ### Domain Name

> Specifies the domain name. Enter the domain name exactly as it was assigned by the NIC Domain Registrar, including its top-level domain extension. For example, enter `school.edu` , `company.com` , or `city.gov` .

> ### DHCP Server

> Enter the IP address or name of the DHCP server.

> ### Hostname Prefix

> Specifies a host name prefix.

> The host name prefix is used when a computer requests a host name and one is not available.

> Using the `mycompany.com` domain as an example, assume:

> - All names in the host name list have been assigned.
> - Host name prefix is magic.

> Then, the DHCP server gives the host names `magic1` and `magic2` to the next two computers that request host names.

> Enter a specific host name prefix.

> ### Host names

> Specifies the list of host names. Enter as many host names as needed. Different DHCP servers can own the same host names.

### 7.5.2.4 Active IP Snapshot

You can use the Active IP Snapshot window to view the lease database, manually add a new lease, and remove a lease.

> ### Viewing a Lease

> The left side of the Active IP Snapshot window lists each DHCP client with a lease granted by the server. To see the details:
> 1. Click the Server/Security tab.
> 2. Choose Active IP Snapshot from the drop-down list.
> 3. Select a record on the left side of the window.
> 4. Review the information on the right side of the window. It lists the information that applies to the selected record.

> ### Adding a New Lease

> Typically you only add a new lease when you intend to permanently attach a hardware address to an IP address. The IP address does not need to come from the DHCP IP addresses you have defined.

> To add a new lease, use the following procedure:

> 1. Click the Server/Security tab.
> 2. Choose Active IP Snapshot from the drop-down list.
> 3. Choose [New Record].
> 4. Enter a value for each parameter.
> 5. Click Add.

> Changes made to the database take effect immediately.

> Note Ensure that the IP address you specify does not belong to any pool of IP addresses configured in an IP range. If it does, it could be released and used by other clients (MAC address). If you want to grant a lease for an infinite period of time, which effectively make a permanent binding between an IP address and a MAC address, set the Lease Expiration parameter to a value of -1.

> ### Removing a Lease

> To remove a lease, use the following procedure:
> 1. Click the Server/Security tab.
> 2. Choose Active IP Snapshot from the drop-down list.
> 3. On the left side of the window, select the record you want to remove.
> 4. Click Delete.

> Changes to the database take effect immediately.

> ### Refreshing the Active IP Snapshot Window

> To refresh the Active IP Snapshot window so that it reflects the current status of the database, click Refresh. This parameter will refresh data on leases that are active or expired, or both.

### 7.5.2.5 Preload MAC Addresses

Use the Preload MAC Addresses window to restrict the assignment of IP addresses. To enable this security measure, set the Restrict to known MAC addr value to True in the Server/Security Parameters window. You can then manually assign the desired MAC addresses. The server ignores all other client DHCP requests.

> ### Checking the Status of a MAC Address

> Each configured MAC address and type is listed on the left side of the Preload MAC Addresses window. To see the details of a MAC address:
> 1. Click the Server/Security tab.
> 2. Choose Preload MAC Addresses from the drop-down list.
> 3. Select a record from the left side of the window.

> The right side of the window lists the information applicable to the address.

> ### Adding a New MAC Address

> Initially, you may need to add large numbers of MAC addresses to the known clients database; it may be more practical to use the command line utility `jdbreg` for this purpose. You would typically use the GUI to add MAC addresses when new (trusted) clients appear on the network.

> To add a new MAC address:

> 1. Click the Server/Security tab.
> 2. Choose Preload MAC Addresses from the drop-down list.
> 3. Choose [New Record].
> 4. Enter a value for each parameter.
> 5. Click Add.

> Changes to the database take effect immediately.

> ### Removing a MAC Address

> To remove a MAC address:
> 1. Click the Server/Security tab.
> 2. Choose Preload MAC Addresses from the drop-down list.
> 3. Choose the MAC address you want to delete.
> 4. Click Delete.

> Changes to the database take effect immediately.

> ### Searching for a MAC or IP Address

> To search for a MAC or IP address:
> 1. Click the Server/Security tab.
> 2. Choose Preload MAC Addresses from the drop-down list.
> 3. Click Find.
> 4. Enter the MAC or IP address you want to locate.
> 5. Click OK.

> ### Refreshing the MAC Addresses Window

> To refresh the MAC address window so that it reflects the current status of the database, click Refresh.

## 7.5.3 Configuring Parameters for Clients

DHCP allows you to configure many client parameters in addition to the client's IP address. For example you can configure the IP address of a client's bind server and its DNS domain name.

There are three ways to assign configuration parameters to DHCP clients. You can assign parameters to:

- A specific client
  To assign parameters to a specific client, use the node configuration options described in Section 7.5.3.2. This is called a node group and is identified by the client's MAC address.
- A net or subnet
  To assign parameters to all clients in a subnet, use the subnet configuration options described in Section 7.5.3.1. This is called a subnet group and is identified by the subnet in which the client is being configured. You will likely configure each client within a subnet with similar parameters, for example, DNS domain name, DNS server, default route, and so forth.
- A group of clients
  To assign parameters to a group of clients that are not in the same subnet, use the group configuration options described in Section 7.5.3.3. This is called an include group. You can declare a node or subnet group as a member of an include group to pull in the include group's parameters.

After the DHCP server finds an IP address for a client, it matches the client's MAC address against your node groups and the client's subnet against your subnet groups, pulling any parameters from matched groups into the list of parameters to be sent to the DHCP client. If a match occurs against both a subnet and a node group, and a particular parameter is assigned in both the subnet and the node group, then the value from the node group is used. When a match occurs on a subnet or node group that is a member of an include group, the DHCP server pulls in parameters from the include group also.

### 7.5.3.1 The Subnets Tab

A subnet is a segment of a logical network that has been divided into smaller physical networks. Use the Subnets tab to configure parameters to be passed to DHCP clients according to the subnet in which they reside.

#### 7.5.3.1.1 Configuring a subnet

You do not have to change every value for the parameters in the Subnets tab.

To configure a subnet group using the Subnets tab, use the following procedure. For a description of the subnet parameters, see Section 7.5.3.4.

1. Click the Subnets tab.
2. Choose [New Record].
3. Choose the Name parameter from the Name/ID Parameters menu.
4. Enter the name of the subnet configuration in the Value field. This name is a tag for internal use of the DHCP server only. For more information, see Section 7.5.3.4.1.
5. Choose Member of Group (optional). Enter the name of the include group that the subnet group is joining. Any client that matches this entry will pull in the parameters from the specified include group.
6. Set up key information:
   1. Choose the net or subnet IP address.
      Enter the net or subnet IP address that identifies the subnet portion of the network.
   2. Choose the vendor class (optional).
      Enter the vendor class (for example, TCPVMS or JOIN) that identifies the DHCP client vendor class to which this entry should apply. Note that you can have multiple subnet entries for the same Net or Subnet IP Address if they have different Vendor Class key values. If the entry should apply to any vendor class or you are not using vendor classes leave the Vendor Class field blank.
7. Choose from the lists of DHCP parameters on the drop-down list.
   Different lists of DHCP parameters are available on the drop down list. Choose either BASIC DHCP Parameters or DHCP Parameters.
8. 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 7.5.3.4.
9. Choose Update from the File menu to update the server with the new configuration.

The new configuration takes effect immediately.

#### 7.5.3.1.2 Removing a Subnet Record

To remove a subnet record:

1. Click the Subnets tab.
2. Choose DHCP Parameters from the drop-down list.
3. Choose the subnet record you want to delete.
4. Click Delete.

Changes to the database take effect immediately.

### 7.5.3.2 The Nodes Tab

A node is a workstation, computer, or other device on the network. Use the Nodes tab to configure parameters to be passed to specific client nodes.

#### 7.5.3.2.1 Configuring a node

You need not change every value for the parameters in the Nodes tab. A node group can be a member of an include group although the settings for a node group override those from a subnet or include group.

To configure a node group using the Nodes tab, use the following procedure. For a description of the node parameters, see Section 7.5.3.4.

1. Click the Nodes tab.
2. Choose [New Record].
3. Enter the name of the node configuration in the Value field. This name is a tag for internal use of the DHCP server only. For more information, see Section 7.5.3.4.1.
4. Choose Member of Group (optional). Enter the name of the include group that the node group is joining. The client that matches this entry will pull in the parameters from the specified include group.
5. Set up key information:
   1. Choose Hardware Address. Enter either the hardware address or the client ID of the node.
      If you are using the hardware address (MAC address) of the node, enter it using the format xx:xx:xx:xx:xx:xx, for example, 00:08:C7:08:E3:63. The hardware address is assigned during manufacturing, and usually appears when you turn on or reboot your computer.
   2. Choose Hardware Type. Enter the type of network the node is connected to: Token Ring, Ether3, Pronet, ARCnet, or 0 (see Table 7-6).
6. Choose from the lists of DHCP parameters on the drop-down list.
   Different lists of DHCP parameters are available on the drop-down list. Choose either BASIC DHCP Parameters or DHCP Parameters.
7. 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 7.5.3.4.
8. Choose Update from the File menu to update the server with the new configuration.

The new configuration takes effect immediately.

Table 7-6 Network Type Symbol and Number
Symbol | Number | Network Type
--- | --- | ---
ethernet or ether | 1 | 10 MB Ethernet
ethernet3 or ether3 | 2 | 3 MB experimental
ax.25 | 3 | AX.25 Amateur Radio
protnet | 4 | Protnet proNET Token Ring
chaos | 5 | Chaos
token-ring,tr,ieee802 | 6 | IEEE802
arcnet | 7 | ARCnet

#### 7.5.3.2.2 Removing a node record

To remove a node record:

1. Click the Nodes tab.
2. Choose DHCP Parameters from the drop-down list.
3. Choose the Node record you want to delete.
4. Click Delete.

Changes to the database take effect immediately.

### 7.5.3.3 The Groups Tab

An include group is a collection of parameters to be passed to a set of workstations or other computers on the network which can be on different subnets. Use the Groups tab to configure include groups.

#### 7.5.3.3.1 Using group parameters

You can define a group so that a set of workstations, possibly on different subnets, has the same configuration values. For example, you might want a group to include specific lease time information for your network environment and you want this lease information to be used for all of your clients. You can define an include group holding this lease information and make your subnet groups members of this include group. The alternative would be to duplicate the lease information in each individual subnet group entry which is more difficult and error prone. Include groups can be members of other include groups. This allows you to create hierarchies of available network services across many clients.

#### 7.5.3.3.2 Defining a group

To define an include group using the Groups tab, use the following procedure. For a description of the group parameters, see Section 7.5.3.4.

1. Click the Groups tab.
2. Choose [New Record].
3. Enter the name of the include group in the Value field. This name is a tag for internal use of the DHCP server only. For more information see Section 7.5.3.4.1.
4. Choose Member of Group (optional). Enter the name of an include group that the include group is joining. Use this feature to create hierarchies of groups and minimize duplication elsewhere.
5. Choose Group Members (optional).
   Enter the names of subnets, nodes, or other groups that are to be members of the group, that will pull in this group's parameters. If you have already created a node or subnet group or groups that are members of the include group you are entering the DHCP GUI will display the names of these groups in the Group Members field. If you want to include a new member or delete an existing member you can do so here in the group's Group Members field or under the Subnets or Nodes tab in the Member of Group field of the groups pulling in this group.
6. Set up key information:
   Enter the vendor class (for example, TCPVMS or JOIN) that identifies the DHCP client vendor class to which this entry should apply. Note that you can have multiple include groups with the same name if they have different vendor class key values. If the entry should apply to any vendor class or you are not using vendor classes leave the vendor class field blank.

7. Choose from the lists of DHCP parameters on the drop-down list.
   Different lists of DHCP parameters are available on the drop down list. Choose either BASIC DHCP Parameters or DHCP Parameters.
8. 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 7.5.3.4.
9. Choose Update from the File menu.

The new configuration takes effect immediately.

#### 7.5.3.3.3 Removing a group record

To remove a group record:

1. Click the Groups tab.
2. Choose DHCP Parameters from the drop-down list.
3. Choose the Group record you want to delete.
4. Click Delete.

Changes to the database take effect immediately.

### 7.5.3.4 Nodes, Subnets, Group Parameters

This section describes the subnet, group, and node parameters. The parameters are grouped by the following categories:

- Name and ID Parameters
- Key Parameters
- BOOTP Parameters
- IP Parameters
- Lease Parameters
- Link Parameters
- NetBIOS Parameters
- Network Parameters
- TCP Parameters
- Time Parameters
- X Window Parameters

For any parameter, list the values in order of preference.

#### 7.5.3.4.1 Name/ID parameters

Name and identification parameters determine the name of the configuration and information that identifies which client or clients are being configured by this record.

> ### Name

> Specifies the name for this subnet, node, or include group configuration. The names used here are tags for the internal use of the DHCP server. You can name them as you choose but do not use the same name more than once except where you use a different vendor class for the duplicate names.

> ### Group Members

> Specifies the names of subnet, node, and include groups that are members of the group (that is, those that inherit this group's parameters).

> ### Member of Group

> Specifies the name of the group that the subnet, node, or include group is joining.

##### 7.5.3.4.1.1 Limitations on Group Hierarchies

The hierarchies provided for with member groups do not support multiple inheritance. An include group can have multiple members, but an include, subnet, or node group can be a member of only one group. For example, you can make Group_A with members Group_B and Group_C, but you can not make Group_A a member of Group_B and Group_C.

#### 7.5.3.4.2 Key Parameters

Key parameters identify the keys for the configuration record. The Key parameters include Hardware Address/Client ID, Hardware Type, Net or Subnet IP Address, and Vendor Class.

> ### Hardware Address/Client ID

> This parameter specifies the hardware address (MAC address) of the node. Enter the hardware address in the format xx:xx:xx:x:xx:xx, for example, 00:08:C7:08:E3:63. The hardware address is assigned during manufacturing and usually is displayed when you turn on or reboot your workstation.

> ### Hardware Type

> This field takes a string of characters and specifies the network type associated with this node, such as Ethernet or token ring.

> Enter either the symbol or the actual number as shown in Table 7-6. For example, to specify Ethernet as the hardware type, enter either the symbol ether or the number 1.

> ### Net or Subnet IP Address

> Specifies the address of the subnet record (if its a Subnet configuration record). Enter the IP address that identifies this subnet portion of the network, for example, 129.84.3.0.

> ### Vendor Class

> A DHCP client can pass a vendor class string to the server to identify the client vendor implementation. For example, TCPVMS for the TCP/IP Services DHCP client. The DHCP server uses the vendor class string as part of the key lookup when determining which groups of configured parameters apply to the client. The information is a string of octets, usually ASCII, that the server interprets.

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