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Understanding
IntranetWare TCP/IP
A supplement to Novell's CNE Study Set -- IntranetWare/NetWare 4.11
by David James Clarke, IV
Featuring:
The Internet's main protocol suite is called TCP/IP. It consists primarily
of IP (Internet Protocol), which provides Network Layer routing, and TCP
(Transmission Control Protocol), which accepts messages from IP and packages
them for Internet-based applications. In addition to IP and TCP, the Internet
Protocol Suite includes a variety of other protocols including FTP (File
Transfer Protocol), SMTP (Simple Mail Transfer Protocol), Telnet, and NFS
(Network File System).
TCP/IP was originally developed by the U.S. Department of Defense (DOD)
in the early 1970s. Back then, it provided packet-switched network connectivity
among government agencies, universities, and research institutions. Today,
TCP/IP is an "open" industry protocol supported by a variety of manufacturers
including Novell, SUN, Apple, DEC, and IBM. TCP/IP offers millions of users
immediate access to a complete spectrum of services and information via
intranets and the Internet. I guess it's safe to say that TCP/IP is the
foundation of our global electronic village.
In this section, we explore a variety of TCP/IP issues, including:
TCP/IP is a great foundation for intranet connectivity because it provides
an open link between your private network and the Internet. Let's surf
the Net using TCP/IP!
Novell's IPX vs. TCP/IP
Both TCP/IP and IPX are excellent networking protocols. Both share many
common elements, including large, installed bases, routability, and a history
of coexistence on LANs and WANs. However, several important differences
exist between TCP/IP-based and IPX-based networks, including:
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The Host
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Addressing
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Locating
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Security
Let's take a closer look.
IPX vs. TCP/IP: The Host
In the IPX world, the term "host" refers to a LAN-based server. An IPX
workstation is not normally considered a host because it is not a service
provider.
In the TCP/IP world, on the other hand, a host can be either a workstation
or a server. This is because both machines offer services to the network.
Addionally, all IP workstations and servers require a unique IP address.
IPX vs. TCP/IP: Addressing
The fundamental difference between IPX and IP addressing can be observed
in the way each is used. The IPX protocol was designed for use on private
LANs and WANs. Therefore, addressing is a high priority. As a CNE, you
need to track only the internal server node and segment addresses on an
IPX LAN. Workstation addressing is built into the NIC and is automatic.
Addionally, you can register your IPX address with Novell or public IPX
network services such as AT&T WorldNet Intranet Connect Service.
IP addressing, on the other hand, is designed for global public network
-- that is, the Internet. As a result, IP addressing is often more complex
and more difficult to track. In summary, IP network, subnetwork, and node
numbers are all defined in a single IP address, which is decoded by its
subnet mask (I explain more about this later). IPX, on the other hand,
automatically references the internal NIC's node number.
If you intend to connect your intranet to the Internet, you will need
to obtain registered IP addresses for public use. Global registration is
handled by the following organization:
Network Solutions
InterNIC Registration Services
505 Huntmar Park Drive
Herndon, VA 22070
You can also obtain assistance by contacting mailto:HostMaster@InterNIC
via electronic mail. Currently, a shortage of registered IP addresses exists,
so you may want to consider registering some hosts even if you don't have
plans for the Internet at this point. In the future, a new version of IP
addressing (called IPng, or IP Next Generation) will help alleviate the
current registered IP address shortage.
In addition to registered IP addresses, you can obtain your own registered
domain name. A domain name is a unique name (such as NOVELL.COM) that identifies
you for Web browsing, e-mail, FTP, and so on. I discuss domain names later
in this section.
REAL WORLD
Most businesses connect to the World Wide Web using an Internet Service
Provider (ISP). In the U.S., several types of ISPs cater to business needs.
First, carrier-level companies such as AT&T, MCI, and Sprint offer
guaranteed Internet connectivity on their respective phone networks. National
ISPs, including Netcom and UUNET, offer high levels of service and competitive
prices throughout the country; they cater primarily to the "dial-up" customer.
Finally, Regional ISPs, such as Earthlink, are usually cheaper than national
ISPs, but may not always offer the latest services.
The business ISPs mentioned above typically offer a variety of hosting,
services including built-in IP addressing, customized billing, T-1 connectivity,
domain name registration, and more.
It just goes to show that in cyberspace, just like anywhere else, you
can always get what you want ... for a price.
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IPX vs. TCP/IP: Locating
IPX and TCP/IP networks differ in the way they locate network services.
Both protocols rely on directories of network hosts, but each does so in
a slightly different way. As you know from previous CNE courses, IPX networks
generally rely on Novell Directory Services (NDS) and/or Service Advertising
Protocol (SAP) for server identification. Of these, NDS is the newest and
preferred solution.
TCP/IP WANs, on the other hand, rely on either Host Tables or Domain
Name System (DNS) servers. Host Tables are typically small text files which
list local host names and their corresponding IP addresses. They are very
impractical because tables must be copied to every TCP/IP server and client.
On most of today's intranets, Host Tables have been replaced by DNS servers,
which keep track of virtually all host names and their addresses on the
Internet. DNS services can be provided by your ISP or by the built-in functionality
of IntranetWare. We'll take a closer look at both of these topics later
in this section.
For more in-depth information on DNS capabilities, see Novell Education
Course 658 -- DNS/FTP Installation and Configuration.
IPX vs. TCP/IP: Security
Finally, IPX and TCP/IP networks differ in the way they handle network
security. In the IPX world, security is primarily enforced by NDS Authentication
(IntranetWare) or the server bindery (NetWare 3.12). It's important to
note that IPX security is service-based, not host-based.
On IP networks, however, firewall security enables you to prevent unauthorized
access to a specific network or host. A firewall is typically a network
configuration consisting of both hardware and software that forms a boundary
between your network computers and the outside world. The computers within
the firewall then form a secure subnetwork with internal autonomy. A variety
of manufacturers create firewall products, including CyberGuard, DEC, and
On Technology. Additionally, Novell has released an advanced firewall for
IntranetWare, called Border Services.
This completes our comparison of Novell's IPX protocol and TCP/IP. Hopefully,
you've gained an appreciation for the intranet-based functionality built
into TCP/IP. In many ways, it has evolved as a perfect platform for our
global electronic village. Now, let's take a closer look at its basic architecture.
SMART LINK
To learn more about TCP/IP security online, consider browsing to one
or more of the following sites:
The Site Security
Handbook RFC
US
National Computer Security Association
US
National Institute of Standards and Technology, Computer Security Resource
Clearinghouse
The TCP/IP Protocol Suite
The TCP/IP Protocol Suite actually encompasses much more than the IP
and TCP protocols. More accurately, it's a group of protocols operating
at five of the seven layers of the OSI (Open System Interconnection) model.
As you undoubtedly recall from your Networking Technologies odyssey
(Course 200), the OSI model is the backbone of our networking galaxy. It
provides a reference point for communications, networking, and application
standards. Today, we're interested in the top five layers and how they
relate to the TCP/IP Protocol Suite.
Additionally, TCP/IP maps to a second standard model developed by the
Department of Defense, called the DOD model (how original). The DOD model
defines four layers that relate to specific TCP/IP functionality. Each
of the four layers maps directly to multiple layers of the OSI model. Here's
how it works (follow along with Figure 540SG-1 below):
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Network Access -- defines the bottom of the DOD model and maps directly
to the OSI Physical and Data Link layers. Network Access standards, including
Ethernet, Token Ring, FDDI, and the 802 Series, are common throughout the
networking industry.
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Internet -- defines the second level of the DOD model and maps directly
to the OSI Network layer. Internet protocols help move data through and
between networks, thus connecting diverse senders and receivers. The two
most popular Internet protocols are IP and ICMP.
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Host-to-Host -- defines the third layer of the DOD model and maps directly
to the OSI Transport layer. Host-to-Host protocols deliver data to, and
receive data from, peer protocols in other network systems. The most popular
Host-to-Host protocols are TCP and UDP (User Datagram Protocol).
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Process/Application -- defines the highest level of the DOD model and maps
directly to the OSI Session, Presentation, and Application layers. Process
protocols provide user application services and an interface for network
connectivity. The most popular Process protocols are HTTP, FTP, Telnet,
SMTP, and NFS.
Figure 540SG-1: Mapping the TCP/IP Protocol Suite to DOD and
OSI Models
As you can see in Figure 540SG-1, the TCP/IP Protocol Suite resides
primarily at the top five layers of the OSI model. The bottom two layers
are occupied by general industry standards (such as Ethernet and Token
Ring). Also, pay attention to the top three layers of the DOD model. This
is where TCP/IP happens. Let's take a closer look.
Internet Layer Protocols
The primary purpose of the Internet Layer Protocols is to route packets
between different hosts. Depending on the network structure, several paths
may be available between the sender and receiver. Internet protocols move
datagrams through the internetwork one hop at a time, by referencing dynamic
tables at each hop. Each router along the way makes a decision about a
datagram's next hop, based on the logical network and physical device addresses.
The two most popular Internet Layer Protocols are:
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IP -- This is the main Internet protocol. IP is a connectionless, packet-switched
implementation that performs logical addressing and dynamic route selection.
It is also responsible for fragmentation and reassembly.
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ICMP -- This is the Internet Control Message Protocol. ICMP works with
IP to provide error and other control information. Because IP is connectionless,
it cannot detect internetwork conditions such as a congested WAN or a failed
path. ICMP is used to notify IP and other upper-layer protocols of flow
control problems.
Host-To-Host Layer Protocols
The Host-to-Host layer of the TCP/IP Suite maintains data integrity
and sets up reliable end-to-end communication between systems. The main
goal of Host-to-Host protocols is to ensure error-free delivery of packets
in the proper sequence, with no loss or duplication.
The two main Host-to-Host layer protocols are:
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TCP -- This is the Transmission Control Protocol. TCP is the main Host-to-Host
Internet protocol. It accepts messages of any length from an upper-layer
application and provides full duplex, connection-oriented transport. To
accomplish this, TCP uses a virtual circuit between hosts and acknowledges
all packets. This ensures a reliable connection for data exchange. TCP
is the protocol of choice for Telnet and FTP applications.
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UDP -- This is the User Datagram Protocol. UDP is closely related to TCP
in that it provides Host-to-Host functionality. UDP is not connection oriented,
however, and does not acknowledge data receipt. Instead, it uses an unreliable,
connectionless delivery system. UDP simply accepts and transports datagrams.
On the upside, UDP isn't burdened by all the bureaucracy of TCP; therefore,
it can transfer data much faster. This is the protocol of choice for TFTP
(Trivial File Transfer Protocol), DNS (Domain Name System), and NFS (Network
File System) applications.
Process/Application Layer Protocols
Protocols at the highest level of the DOD model operate much like server
NLMs (Novell Loadable Modules). Typically, these processes are not continually
running on the host machine. Instead, they are triggered by certain events,
such as client requests. Of course, Novell's Web Server is an exception
-- it's open 24 hours a day. In the simplest terms, these are the applications
that interface with TCP/IP users.
Some of the most popular Process/Application layer protocols are:
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Telnet -- This is a remote control protocol for contolling UNIX-based hosts.
Using Telnet is much like using RCONSOLE in the NetWare environment.
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FTP -- This is the File Transfer Protocol. FTP enables a user to transfer
files between two networked computers. It also provides a variety of login,
directory inspection, file manipulation, command execution, and other Application
services. FTP also has a sister protocol called TFTP (Trivial File Transfer
Protocol). In a later section, we'll explore Novell's FTP solution: FTP
Services for IntranetWare.
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NFS -- This is the Network File System protocol. It provides file sharing
capabilities between users of dissimilar computers.
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SMTP -- This is the Simple Mail Transfer Protocol. SMTP is an electronic
mail routing standard that uses TCP and IP to route mail messages between
network hosts. SMTP does not provide a local mail user interface, so you'll
have to go find one of your own (such as Netscape).
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X Windows -- This is an Internet-based application sharing environment.
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RPR -- This is the remote printing protocol and is an Internet-based remote
printing application.
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SNMP -- This is the Simple Network Management Protocol. SNMP is a troubleshooting
application built into hardware at the Network Access level. You can use
SNMP to remotely monitor the health of distant Internet hosts.
This completes our journey through the fundamental architecture of TCP/IP.
Hopefully, you've gained an appreciation for its power and complexity.
As a citizen of the global electronic village, you'll need to understand
the TCP/IP "rules of the road" in order to survive. The most fundamental
rule is Addressing -- that is, how do you identify the road you're traveling
on and the address of your destination?
Easy . . . you use a virtual e-map. Check it out.
Understanding IP Addressing
Now that you understand what the TCP/IP protocol looks like, let's take
a moment to explore how it works. Addressing is the most basic law of the
information superhighway. After all, you can't successfully travel from
point A to point B if you don't know where point B is! Earlier, we learned
that one of the simple strengths of TCP/IP is that it treats every host
on the network equally; therefore, each host must have its own unique IP
address. The IP address is a unique software identifier that contains two
important pieces of information:
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Network Address -- All hosts on the same network segment must use the same
network address.
-
Node Address -- Each host on the same network must have a unique node address.
By convention, the IP address uses a four-byte (32 total bits) dotted decimal
notation scheme. In the following example, the first three numbers (206.127.205)
represent the network segment, and the final number identifies the specific
host (131):
206.127.205.131
Now, let's take a closer look at three important aspects of IP addressing:
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IP Address Classes
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Assigning Your IP Address
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Host Naming
IP Address Classes
The global electronic village has zillions of cyber-citizens; therefore,
we need a way to classify different types of hosts. Earlier we learned
that IP addresses combine both the network and node address into one identifying
number. Classes help hosts determine which portion of the IP address is
the network address and which portion is the node address. As you can see
in Figure 540SG-2 below, Class A, B, and C networks have increasingly larger
network address fields.
Here's how it works:
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Class A Networks -- The first octet (8 bits) identifies the network segment,
and the final three octets identify the node. In this scheme, the first
bit must be a zero ("0"), leaving a total of 127 available network segments.
If this seems limiting, consider that each segment can host up to 16,777,216
hosts. Virtually all Class A addresses have already been assigned by InterNIC.
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Class B Networks -- The first two octets are used to identify the network
segment, and the last two octets identify the host. This is the most common
network type on the Web, and is reserved for universities and commercial
organizations. In a Class B scheme, the first two bits are "10," therefore
limiting it to the 128 to 191 address range. There are 16,384 possible
Class B network segments, each with up to 65,534 hosts. Relatively few
Class B addresses remain available from InterNIC.
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Class C Networks -- The first three octets identify the network segment,
and the last octet is assigned to the host. In this scheme, the first three
bits must be "110," therefore confining it to the 192 to 223 address range.
There are 2,097,152 possible Class C network segments, each hosting up
to 254 nodes.
Figure 540SG-2: Understanding IP Address Classes
Fortunately, these complex, dotted, decimal addresses can be converted
into more user-friendly names. This is accomplished using Host Naming,
which we'll discuss in a moment. But first, let's learn how to assign IP
addresses to custom networks and nodes.
Assigning Your IP Address
Once you register a valid network address to your segment, you can assign
individual node addresses to each of your hosts. For example, if your Class
C network address is 206.127.0.0, you can assign any combination of node
addresses to IP workstations and servers:
206.127.0.1
206.127.0.131
206.127.0.254
There are, however, a few special IP addresses of which you should be aware:
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0.0.0.0 refers to the default route used to simplify IP routing
tables.
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127.0.0.0 is reserved for loopback.
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255.255.255.255 is reserved for broadcasts.
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0.0.x.x is an address with all Network bits set to zero. This refers
to the current network. Class B only.
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x.x.0.0 is an address with all Host bits set to zero. This refers
to the network segment itself. Class B only.
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0.0.255.255 refers to all hosts within a given network segment.
If you obtain a block of addresses from an ISP (Internet service provider),
you can use the addresses within the block without worrying about address
classes or special IP addresses. This is the responsibility of the ISP.
Also, determine whether your ISP addresses are nontransferable. Sometimes,
the ISP reserves the right to take back the addresses if or when you discontinue
their service.
Host Naming
All of this cyberspace numerology is fascinating, but what does it mean
to simple Web surfers? Not much.
Fortunately, these complex dotted decimal addresses can be converted
into more user-friendly names. This process is called Host Naming. You
can accomplish host naming in one of two ways:
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Host Table
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Domain Name System (DNS)
A Host Table is an ASCII file containing the names and addresses of systems
that you commonly access. If you are trying to establish a Telnet session
with the host cyberstateu.com, for example, the Host Table will tell your
browser exactly where to go. As you can see in Table 540-1, the ASCII file
uses the following syntax:
Internet Address [space] Official Host Name [space] Aliases
Any number of blanks and/or tab characters separate items. On UNIX systems,
the file is called "/etc/hosts" and on an IntranetWare server,
the file is "SYS:ETC\HOSTS."
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Table 540SG-1: A Sample
Host Table
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| Internet Address |
Official Host Name |
| 206.127.205.127 |
World-Wire.com |
| 206.127.205.130 |
Learning-Ware.com |
| 206.127.205.131 |
CyberStateU.com |
While a Host Table is convenient when looking up addresses within your
cyber-neighborhood, keeping a library of up-to-date addresses for every
host in the world is impractical. This virtual magic is accomplished using
a Domain Name System (DNS). The DNS is structured like an inverted tree,
much like the directory structure of an IntranetWare volume. Each node
on the tree represents a domain starting at the Root.
Table 540.2 lists the most common Internet DNS domains, by function.
The full name for any given host is constructed by listing all the names
from the host to the Root. As with NDS naming, a period is used to separate
names. For example, the following DNS name identifies the education department
within the Novell corporate domain: education.novell.com. See Figure 540-3.
Figure 540-3: How this Novell address is formed.
See Table 540-2 for a breakdown of some common DNS domains.
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Table 540SG-2: Common
DNS Domains
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| DNS Domain |
Function |
| COM |
Businesses |
| EDU |
Colleges and universities |
| NET |
Gateways or hosts |
| ORG |
Other organizations |
| MIL |
Military sites |
| GOV |
Government sites |
| AU |
Two-character country code
for Australia |
This concludes our brief romp through TCP/IP addressing rules. Hopefully,
now you have an appreciation for what the TCP/IP protocol looks like and
how it helps you surf the information superhighway. Now, let's complete
our TCP/IP odyssey with a quick look at Novell's solution: IntranetWare
TCP/IP.
Installing IntranetWare TCP/IP
IntranetWare support for TCP/IP is provided through Novell's Internet
Access Server (NIAS) and/or NetWare 4.11. Also, make sure you are using
the latest version of Novell's TCP/IP drivers. Ironically, you can find
them on the Internet.
Once you've installed NIAS on the IntranetWare server, you can configure
it to support TCP/IP. Once TCP/IP is installed on your IntranetWare server,
you can activate the other NIAS services, such as IPX/IP Gateway, Novell
Web Server, and FTP Services for IntranetWare.
To configure the IntranetWare server for TCP/IP, complete the following
steps:
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First, ensure that TCPIP.NLM has not already been loaded. You can check
this by typing CONFIG at the server console. If TCPIP.NLM is already loaded,
unload it now.
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At the server console, type Load INETCFG.NLM. If you are asked whether
to transfer your LAN driver protocol and remote access commands, choose
Yes and press Enter. This will move the LOAD and BIND commands from the
server AUTOEXEC.NCF file to INETCFG's startup files. Next, you may receive
one or more duplicate load errors saying that a particular statement was
not imported. If so, press Enter to continue after each.
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From the Main Menu, select Protocols, and then choose TCP/IP.
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Specify Enabled in the TCP/IP Status field so that the protocol becomes
operational. Press Esc to return to the previous menu and select Yes when
the Update TCP/IP Configuration? prompt appears. Finally, press Esc to
return to the main INETCFG menu.
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To bind a local address and subnetwork mask to the internal server NIC,
select Bindings from the INETCFG main menu. Next, press Ins and select
TCP/IP. Then, select A Network Interface when the Bind to? prompt appears.
Next, select your NIC from the list of configured network interfaces. Finally,
type the local IP address and subnetwork mask in the correct fields and
press Esc.
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Select Yes and press Enter when the Update TCP/IP configuration? prompt
reappears. You're done! Exit INETCFG and save the changes you've made.
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DOWN and Restart the server so that the changes take effect.
Congratulations! You've done it!
You've successfully poured the concrete of your on-ramp to the information
superhighway. In this section, we've learned that TCP/IP is the glue that
holds together our global electronic village. It routes messages between
hosts using the IP protocol and ensures reliable delivery with TCP. We've
discovered the sophisticated TCP/IP architecture and mastered IP addressing.
Additionally, we've armed our IntranetWare server with TCP/IP power.
Now, we're ready to attack the three main solutions of Novell's global
electronic village:
IPX/IP Gateway
The Novell Web Server
FTP Services for IntranetWare
Ready, set, surf!
Forward to IPX/IP Gateway
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