The first tab you see is IP Address, shown here in figure 8.10. Figure 8.10 shows the entries on this tab. The following list describes the entries:
◆ Adapter. On multihomed hosts, this field enables you to select the interface currently being configured.
◆ Obtain an IP address from DHCP server. This button enables this host
as a DHCP client.
Figure 8.10
The IP Address tab.
◆ Specify an IP address. This button enables manual addressing and activates the three address fields.
◆ IP Address. If manual addressing is active, you must specify the host IP address in this field.
◆ Subnet Mask. If manual addressing is active, you must specify the network subnet mask in this field. All hosts attached to the same IP network segment must be configured with the same subnet mask.
◆ Default Gateway. This field is optional and specifies a default router address. This field is required if you want to talk to hosts on other networks.
DNS Properties
As was introduced in Chapter 3, “The Application Layer,” DNS is basically the process of resolving a host name to an actual IP address so that the system can figure out whether the address is local or remote and resolve it to a MAC address. This is one of the methods available for resolving the names. Primarily this resolves names for utilities that use the WinSock API—in other words, names other than NetBIOS names (see fig. 8.11).
Figure 8.11
The DNS Properties page.
The following list briefly describes the fields and their purposes:
◆ Host Name. This is the name that other hosts see you as. By default, this is the same as the NetBIOS computer name and in most cases should be left as such.
◆ Domain. This is not an NT domain; rather this is the domain that your company has registered on the Internet (for example, Learnix.ca or Microsoft.com). This, together with your host name, makes up your Fully Qualified Domain Name (FQDN)—the name your computer has on the Internet.
◆ DNS Service Search Order. This is a list of computers that run a Domain
Name Service. This resolves the FQDNs into TCP/IP addresses. Windows NT can act as a DNS server. (This is covered in a later chapter.)
◆ Domain Suffix Search Order. To speed up searches for computers from your
own domain, you can enter the domain suffix (the Domain you entered already). The DNS first looks for the host in the domain files for the suffix you specify.
WINS Address Properties
The WINS Address tab is really a general purpose tab for configuring NetBIOS name resolution options (see fig. 8.12). Just as you need to have a way to resolve the FQDNs such as www.newriders.com, you also need some way for your computer to find the other NetBIOS host on your network. WINS (Windows Internet Naming Service) enables you to do this. WINS even handles the dynamic addressing that you receive from DHCP. (NetBIOS name resolution is done differently than host name resolution. These are covered in Chapter 12, “NetBIOS Name Resolution,” and Chapter 15 respectively.)
Figure 8.12
The WINS Address tab.
Here is a brief list and an explanation of the contents of the WINS Address tab:
◆ Adapter. Each of the adapters in the computer can use a different WINS server. This is not usual.
◆ Primary WINS Server. WINS servers are identified by their IP addresses. To enable a host as a WINS client, enter the IP address of a WINS server in this field.
◆ Secondary WINS Server. Any network that uses WINS should be config-
ured with at least two WINS servers (to provide backup in case one fails). You can specify the IP address of a fallback WINS server in this field.
◆ Enable DNS for Windows Resolution. If you check this box, DNS be-
comes the host’s preferred means of resolving host names. This is useful only in cases where the majority of hosts on the network are using Unix or some other non-Microsoft operating system.
◆ Enable LMHOSTS Lookup. If you check this box, the host consults
LMHOSTS files if other resources cannot resolve a name. Chapter 12 examines the LMHOSTS file in greater detail.
◆ Import LMHOSTS. If you have already created an LMHOSTS file that is
correct for this network, you can use this button to open a browse box where the file can be selected for import. The file is placed (by default) in
C:\winnt\system32\drivers\etc.
◆ Scope ID. This field is usually left blank except in high-security environments. Scope IDs establish groups of computers that can communicate with each other, and only hosts that have the same scope ID can communicate using NetBIOS. By default, the Scope ID field is left blank, and all hosts with a blank scope ID can communicate. Note that this does not affect Winsock communications.
DHCP Relay Agent
The DHCP Relay Agent enables an NT server sitting on one subnet to act as a go- between for DHCP clients on that subnet and a DHCP server on another subnet. This makes automatic IP configuration possible even if the client cannot normally broad- cast to the DHCP server (see fig. 8.13).
The options for the Relay Agent include the following:
◆ Maximum hops. The greatest number of networks that can be crossed trying
to get to the DHCP server.
◆ DHCP Servers. The address for one or more DHCP servers that can provide
an address on this network.
Objective
Routing
The Routing tab contains only one option: the Enable IP Forwarding check box (see fig. 8.14). Checking this box enables a multihomed NT computer to function as an IP router (as discussed in the preceding chapter, “Routing”).