Lesson 1

Determining Name Resolution Requirements

4-13

Important

If you plan to use your ISP’s DNS servers for any functions other than client name

resolution, be sure that the DNS server implementation they are using is compatible with the Win-

dows Server 2003 DNS servers you are using, and that they are able to provide the services you

need.

You might also want to consider splitting up these functions by using several DNS serv-

ers. For example, you can use your ISP’s DNS servers for client name resolution even

if you are running your own DNS servers for other purposes. The main advantage of

using your ISP’s servers is to conserve your network’s Internet bandwidth. Remember

that the Internet name resolution requests that DNS servers receive from client resolv-

ers are recursive queries, giving the first server responsibility for sending iterative que-

ries to other DNS servers on the Internet to resolve the name. When the DNS server

receiving the recursive queries is on your private network, all the iterative queries the

server generates and their responses go through your Internet access router, using your

bandwidth (see Figure 4-4). If your clients use a DNS server on your ISP’s network

(which is nearly always a free service), only one query and one response go through

your router. The ISP’s DNS servers generate all the iterative queries, and these queries

travel directly to the Internet.

Requests/Replies

Request

Internet

Reply

Resolver

Internal

WAN Connection

DNS Server

Requests/Replies

Request

Reply

Internet

Resolver

WAN

ISP's DNS

Connection

Server

F04pm04

Figure 4-4

Using the ISP’s DNS server saves Internet bandwidth

Using NetBIOS Names

If computers on your network are running versions of Microsoft Windows earlier than

Windows 2000, they are using NetBIOS names and must have a means of resolving

those names into IP addresses. When Microsoft originally incorporated networking

capabilities into the Windows operating systems, it relied on NetBIOS names to identify

computers and on the NetBEUI protocol for communications. NetBEUI uses these