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MCSE Help : 70-059 -  Internetworking TCP/IP with Microsoft Windows NT 4.0. (Part 1)
Richard Adams guides us through the first of the electives with examination 70-059, Internetworking TCP/IP with Microsoft Windows NT 4.0

Welcome to this month’s MCSE Help! feature. Over the last few months I have been offering advice on each of the core examinations that must be taken in order to gain your MCSE award. This month I am pleased to be able to start on the electives, beginning with exam number 70-059 Internetworking TCP/IP with Microsoft Windows NT 4.0.

General Advice

As we all know, four out of the six examinations needed for obtaining MCSE are non-optional, core subjects: Networking Essentials, Windows NT Server, Windows NT Server in the Enterprise and either Windows 95 or Windows NT Workstation. Having passed these four examinations, you must then decide upon which two elective examinations to take. Almost everyone opts to take TCP/IP as one of their two electives, simply because almost every network runs on TCP/IP and an understanding of TCP/IP is essential in order to successfully install and administer other applications such as Internet Information Server, SQL Server or Exchange Server. The TCP/IP exam is quite theoretical, so you must be able to perform binary to decimal conversion and be able to understand very basic logic operations. You cannot take any equipment into the room with you, but you will be provided with a computer-based calculator with a binary and decimal conversion function.

Exam Breakdown

The TCP/IP exam has 5 sections: Planning, Installation and Configuration, Connectivity, Monitoring and Optimisation and Troubleshooting. As before, we will take a section at a time, list the different subjects that you could get asked about in that section and then give hints and tips on the types of pitfalls and traps you might come across in any one particular question. This month’s article examines the first two of these sections.

The Planning Section

What to Revise

Name Resolution Methods, Multihomed Computers, Choosing a Subnet Mask, DNS & WINS, DNS Aliases, Configuring DNS with WINS, WINS replication, LMHOSTS Options, Domain Functions over Multiple Subnets, DHCP scopes and Reservations, SNMP, Determining Number of Host IDs, Fault tolerance with DHCP, WINS records for Multihomed Computers, DNS Server Types
.

Watch For:

1. Name Resolution Methods

Familiarise yourself with the following name resolution methods and in which circumstances to use each one: HOSTS, LMHOSTS, DNS, WINS.

2. Multihomed Computers

To configure a multihomed computer, simply assign a valid IP address to each NIC (Network Interface Card). To make the multihomed computer, enable IP forwarding from TCP/IP properties. To enable dynamic configuration of the routing table, install the RIP for IP service.

3. Choosing a Subnet Mask

The factors to consider when choosing an appropriate subnet mask for your network are the number of subnets, the class of IP address, the number of hosts on each subnet and future growth.

4. DNS & WINS

You will be asked scenario-based questions about when and how to install and configure these two services. Remember that you only need to install your own DNS server if you have an intranet with either Unix or Macintosh computers on it. If your network is completely Microsoft (and even if you are connecting to the Internet) you do not need to install your own DNS server.

5. DNS Aliases

Sometimes you may have a host which requires multiple hostnames (for example if a host is both the Web server and the mail server then it may be called www and mail). The standard A record in DNS should only be used for one name per host. Subsequent names should be configured using a CNAME record.

6. Configuring DNS with WINS

If you are using DHCP to assign IP addresses to hosts, or if you are using either Unix or Macintosh computers alongside Microsoft computers using NetBIOS names, you may need to configure the DNS server to query the WINS server. Because DNS is static, it cannot resolve dynamically changing IP addresses that may occur when using DHCP. Similarly, being for Host names only, it cannot resolve NetBIOS names. To allow WINS resolution, configure the properties of the zone on the primary DNS server.

7. WINS replication

It is recommended that you have more than one WINS server on your internetwork to provide fault tolerance for name resolution. If you do this, you must replicate their databases to each other in order for them to have a full list of name-to-ip-address data. If you configure a WINS server as a pull partner it is configured to collect data from the other WINS server on a schedule. If you configure a WINS server as a push partner it is configured to give data to the other WINS server once a set number of updates have occurred to its database. You may get a scenario-based question regarding this.

8. LMHOSTS Options

There are several entries that you can make in an LMHOSTS file:

Entry Name Purpose
#PRE Preloads the specified entry into the cache for fast access
#DOM:domain Informs the system of the name of a domain controller
#INCLUDE filename The path to and name of another LMHOSTS file to be parsed as if it were part of the local one
#BEGIN_ALTERNATE Allows multiple #INCLUDEs to be grouped together.
#END_ALTERNATE Used in conjunction with #BEGIN_ALTERNATE


9. Domain Functions over Multiple Subnets

If your domain spans multiple IP subnets, it is strongly recommended that you deploy WINS to allow domain functions to operate successfully. If you elect to use LMHOSTS instead, you will need to configure each LMHOSTS file with certain entries in order to be able to support domain browsing, log on and synchronisation.

Domain Function Requirement
Browsing Each Backup Browser must have a #PRE #DOM: entry for the Master Browser. The Master Browser must have a #PRE #DOM: entry for each of the Backup Browsers.
Logging On Each workstation on a subnet that has no domain controllers must have a #PRE #DOM: entry for at least one domain controller
Synchronisation Each Backup Domain Controller must have a #PRE #DOM: entry for the Primary Domain Controller. The Primary Domain Controller must have a #PRE #DOM: entry for each of the Backup Domain Controllers


For fault tolerance it is recommended that each BDC and/or Backup browser also have entries for the other BDCs and Backup browsers in case the PDC or Master Browser goes offline and another one is promoted to that role.

10. DHCP scopes and Reservations

Certain hosts (such as routers used as default gateways) are referenced from other hosts by their IP address. If you are using DHCP to assign IP addresses, you must make sure that the address assigned to such hosts is always the same. To reserve an IP address for a host you must specify both the IP address and the hardware (or MAC) address of the host.

11. SNMP

To provide SNMP support over TCP/IP you need to install the SNMP service.

12. Determining Number of Host Ids

The factors to consider when determining the total number of hosts IDs required on a network are one per host and one per router interface.

13. Fault tolerance with DHCP

It is recommended that you have at least two DHCP servers for fault tolerance. Assign 75% of the total number of IP addresses for the local subnet to a scope on the local DHCP server and assign the other 25% to a scope on a remote DHCP server. Repeat this for each subnet and configure a DHCP relay agent for each subnet. In this way, if the local DHCP server fails, there will be at least some IP addresses available for assignment.

14. WINS records for Multihomed Computers

Only one IP address can be automatically registered by a WINS client. If you have any multihomed computers, you will need to add manual records for all but the first IP address. The record type to use is called MULTIHOMED.

15. DNS Server Types

A Primary DNS server maintains the read/write master copy of a zone file.

A Secondary DNS server maintains a read-only backup copy of a zone file

A Cacheing-Only DNS server does not maintain a copy of a zone file and is used to cache previous requests for fast resolution. Cacheing-Only DNS servers are often configured as DNS Forwarders, which means that they can query other DNS servers for out-of-zone resolution requests.

The Installation and Configuration Section

What to Revise:

TCP/IP Printing
DNS Resolution
Subnetting
Router Configuration
DHCP Options
SNMP Trap Configuration
DHCP Configuration
DNS Record Types


Watch For:

1. TCP/IP Printing

To allow Unix workstations to print to a printer using Windows NT, install the TCP/IP Printing service then share the printer as usual. The three components installed with the TCP/IP Printing service are:

LPD – The print server service (or daemon)

LPR – The client service that allows print jobs to be submitted to a print daemon.

LPQ - The client service that allows the print queue to be remotely queried.

2. DNS Resolution

The file used to resolve host names via the Internet root servers is called DNS.CACHE

3. Subnetting

The most essential part of this section (and perhaps of the entire exam) is a thorough familiarity with subnet masks. You will be given several questions (some scenario-based) on custom subnet masks. The tables for classes A, B and C of address are shown below. You can work it out from scratch in the exam, but I recommend memorising the tables and replacing them onto paper as soon as you get into the exam room – that way you can’t go wrong. Memorising the tables is not hard, as the first column is doubled +2 from the top down and last column is the reverse (doubled and add 2 from the bottom up).

Class A

No of Subnets No of Bits Subnet Mask Hosts per Subnet
0 1 invalid invalid
2 2 255.192.0.0 4,194,302
6 3 255.224.0.0 2,097,150
14 4 255.240.0.0 1,048,457
30 5 255.248.0.0 524,286
62 6 255.252.0.0 262,142
126 7 255.254.0.0 131,070
254 8 255.255.0.0 65,534


Class B

No of Subnets No of Bits Subnet Mask Hosts per Subnet
0 1 invalid invalid
2 2 255.255.192.0 16,382
6 3 255.255.224.0 8,190
14 4 255.255.240.0 4,094
30 5 255.255.248.0 2,046
62 6 255.255.252.0 1,022
126 7 255.255.254.0 510
254 8 255.255.255.0 254


Class C

No of Subnets No of Bits Subnet Mask Hosts per Subnet
Invalid 1 Invalid Invalid
2 2 255.255.255.192 62
6 3 255.255.255.224 30
14 4 255.255.255.240 14
30 5 255.255.255.248 6
62 6 255.255.255.252 2
Invalid 7 Invalid Invalid
Invalid 8 Invalid Invalid


4. Router Configuration


To configure routers manually use the ROUTE ADD command. The syntax for this command is:

ROUTE ADD [destination net ID] MASK [netmask] [gateway address]

5. DHCP Options

Global Options are options configured for all scopes on the DHCP server. This would commonly include WINS Server, Node Type and DNS Server settings

Scope Options are options configured for a specific scope only. This would commonly be the Default Gateway.

6. SNMP Trap Configuration

You need to know the community name and the IP address of the SNMP management station in order to configure NT to send traps.

7. DHCP Configuration

Each scope can be configured with its own lease duration. A longer lease duration is less efficient with IP addresses but requires less network traffic.

A DHCP relay agent must be present on any subnet containing DHCP clients that does not have a local DHCP server present.

If you are configuring DHCP to assign the IP address of a WINS server to its client, you must also configure it to assign a node type. The recommended node type is H, which corresponds to a hexadecimal value of 0x8. The node types are described below.

Node Type Description
B Broadcasts to resolve NetBIOS names
P Contacts a WINS server to resolve NetBIOS names
M Mixed – uses a broadcast followed by a WINS Server if the broadcast was unsuccessful
H Hybrid – uses a WINS Server followed by a broadcast if the WINS Server was unsuccessful


8. DNS Record Types

Although there are many types of DNS records that can be added to a zone file, the only ones that you are likely to be tested on are the following:

Record Name Description
A Standard host name
AAA IPv6 host name
CNAME Alias (for hosts with multiple names)
MX SMTP mail server
PTR Inverse resolution record


Richard Adams is an executive technical director for Additional Resources, an IT training company