NetWare 6 DNS/DHCP Objects NetWare 6 allows you to integrate DNS/DHCP services into eDirectory by extending the schema and creating new eDirectory objects. These objects represent a variety of IP entities, including DNS/DHCP Servers, Groups, Zones, Subnet Pools, and Resource Records. Integrating these new objects into eDirectory simplifies your life and enables centralized configuration of the IP network. This is a good thing! For you to become an IP management pro, you must understand the functionality of all 11 NetWare 6 DNS/DHCP eDirectory objects. These objects are organized into three "buckets": Global DNS/DHCP Objects These objects are created automatically when you extend the eDirectory schema. This category includes three DNS/DHCP objects DNSDHCP-GROUP, DNS-DHCP LOCATOR and the RootServerInfo zone. DNS Objects These objects allow you to manage domain name services from the central eDirectory. This category includes three eDirectory objects: DNS Zone, DNS Resource Record Sets (RRSet), and the DNS Name Server object. DHCP Objects These objects allow you to assign IP addresses dynamically from the central eDirectory database. This category includes five DHCP objects: DHCP Server, DHCP Subnet, DHCP SAR, IP Address, and the Subnet Pool object.
Let's take a much closer look at these 11 DNS/DHCP eDirectory objects, starting with the Global objects. TIP Novell recommends that you place the DNS/DHCP objects very high in the eDirectory tree when you extend the schema. Doing so facilitates universal access to IP management data, such as IP addresses and configurations. For example, we recommend that you place the DNS/DHCP objects in a container no more than two levels below the [Root]. Also consider partitioning the host container and replicating it to distributed, remote locations. Global DNS/DHCP Objects As soon as you extend the eDirectory Schema, three global DNS/DHCP objects are created automatically. It is important to note that only one Group object and one Locator can exist in any given eDirectory tree. Subsequently, the DNS/DHCP servers, DHCP servers, and DNS/DHCP console tools must have access to these objects. Following is a brief description of the three global DNS objects created automatically during eDirectory schema extension: DNSDHCP-GROUP Group Object The DNSDHCP-GROUP object offers an easy method for providing the rights granted to new DNS/DHCP objects to other objects in the tree. By default, the DNSDHCP-GROUP object is given the Browse object right and the Supervisor property right to all new DNS and DHCP objects you create. This way you can guarantee access to DNS/DHCP information for any eDirectory object by simply assigning it as a member of the DNS/DHCP-GROUP object. NetWare servers that you designate as DNS and/or DHCP servers are automatically made members of this Group. DNS-DHCP Locator Group The DNS-DHCP Locator object contains global defaults and DHCP options. It also contains a list of all the DNS/DHCP entities in the tree, including servers, subnets, and zones. The purpose of the DNS-DHCP Locator object is to help you and your management tools find all the DNS/DHCP objects you need without having to search the entire eDirectory tree. (Note: The DNS-DHCP Locator object is not configurable; therefore, it is not displayed in ConsoleOne or NetWare Administrator.) RootServerInfo Zone Object The RootServerInfo Zone object contains the IP addresses of the Root servers on the Internet. It enables you to resolve domain names that belong to zones outside your current zone. Root servers are DNS servers that are maintained on the Internet as top-level phone books. The RootServerInfo Zone object is a portal to link you to the Internet so that your hosts can find other public zones.
That completes our exploration of the three automatically created DNS/DHCP objects. In addition to these three, you can manually create eight other objects after you extend the schema. Let's continue with a description of the three DNS eDirectory objects. DNS Objects Three new DNS objects are available after you extend the eDirectory Schema. These objects help you centrally manage the relationship between DNS host naming and IP addressing. Later in this chapter, we'll explore these objects in detail and learn how to create and configure them. For now, here's a brief description: DNS Zone Object This is an eDirectory container that holds all the data for a single DNS zone. This is the quintessential DNS object. The DNS Zone object contains data that correlates to a variety of DNS- specific entities, including: Start of Authority (SOA), Resource Records (RR), a list of all eDirectory servers that support the DNS Zone, and appropriate server information. It's important to note that the DNS Hierarchy is not represented within the eDirectory tree. A Zone object and its children, for example, might display as peers within eDirectory, even though they have a parent-child relationship in DNS. DNS Server Object This is a separate logical entity from the standard NetWare 6 Server object. The DNS Server object carries out zone instructions and contains specific configuration parameters, including: a zone list, DNS server IP address, server options, and a forwarding/no-forwarding list. This object can be housed within an Organization, Organizational Unit, Country, or Locality container. DNS Resource Record Set (RRSet) Object The DNS RRSet object contains all the Resource Records for a specific zone. Resource Record objects store naming data for each DNS server. It's important to note that the RRSet is created automatically when you build one or more Resource Records. The RRSet contains the following DNS information: DNS Domain Name, a DNS address class, and a Time-to-Live (TTL) Record. Finally, the DNS Resource Record object contains the Record type and data of its host RR.
Now let's complete our DNS/DHCP object lesson with the final five DHCP objects. DHCP Objects Five new DHCP objects are available after you extend the eDirectory Schema. These objects help you to centrally manage IP address assignments and subnet attributes. Later in this chapter, we will explore these objects in detail and learn how to create and configure them. For now, here's a brief description: DHCP Server Object This represents the DHCP server and contains a multivalued attribute listing of the Subnet Ranges this DHCP server is supporting. The DHCP Server object also contains all server-specific configuration and policy information. A DHCP Server object can be housed in an Organization, Organizational Unit, Country, or Locality container. DHCP Subnet Object This is the most fundamental DHCP object in the eDirectory tree. The Subnet object acts as a container for IP Address and SAR objects. A Subnet object's specific DHCP options and configuration parameters apply to the entire subnet and override global options. DHCP SAR Object This is the SAR object. The SAR is primarily used to identify a range of addresses (or pool) for dynamic address assignment or exclusion. Additionally, the SAR object stores the start of a host name that can be assigned to clients when addresses are given. Typically, you should use multiple address ranges under a single Subnet object. This gives you the most flexibility for eDirectory DHCP IP address assignment. IP Address Object This represents a single IP address. The IP Address object can be assigned manually, automatically, or dynamically. For dynamic or automatic assignment, DHCP creates an IP Address object under the Subnet where the address is to be assigned. If you want to create this object manually, you must use the appropriate DNS/DHCP tool. When configuring an individual IP Address object, you can provide specific options that override any existing Global or Subnet parameters. Subnet Pool Object This provides support for multiple subnets through a DHCP or BOOTP forwarder by identifying a pool of subnet addresses for remote address assignment. A Subnet Pool object can be housed in an Organization, Organizational Unit, Country, or Locality container.
That completes our conceptual journey through the virtual world of NetWare 6 DNS/DHCP Services. In this lesson, we've learned how DNS servers translate complex numerical addresses into humane host names, and how DHCP assigns IP information to IP clients. Don't underestimate the administrative power of these two Internet protocols. Is that enough conceptual overview? Are you ready to get to work? We hope so. Theory is important, but now it's time for action. Next, we will tackle DNS/DHCP configuration. |