Dialup Networking with TCP/IP

by Johannes Helmig [Published on 15 Aug. 1998 / Last Updated on 15 Aug. 1998]

You intend to setup a configuration like:

where a TCP/IP connection is required for either connection to a mainframe (which is most often done via TCP/IP) or to other systems on a company internal Wide-Area-Network (WAN).
In such configuration, you need to be aware about a limitation of Windows95/98 ( as it is documented in detail in the Resource Kit) :


That forces the use of Windows NT workstation (or server) as a Dialup Networking server (and in some cases forces the presence of a Windows NT server, see below)

1) Setup of Windows NT workstation as RAS server

I am starting with an NT4 workstation, connected to both a Novell Netware server (using IPX/SPX) and to a Windows NT4 server (using TCP/IP).

For the connection to the Novell Netware
server, "Client Service for Netware"
is installed.
However, to keep it simple, I will
configure RAS only for connection to
the Windows NT server and other TCP/IP
connections
( for connection to Novell, see :
Dialing in via NT4 RAS/DUN to Netware)
TCP/IP is configured for a private range
of IP-addresses.

I start now the installation of RAS (the modem is already installed and configured):

It starts up directly the
configuration of RAS, asking
to add the modem as
RAS device.
Since I like to use this
system also for my connection
to the Internet, I configure it
for "Dial in and Receive Calls"
I configured the Network for
TCP/IP for my dialout
connection (to the Internet) and
the Server setting in this case
only for TCP/IP.
I need to configure the
TCP/IP settings.
I like to connect not just to the
Windows NT station, running
RAS, but to ALL systems on
the entire Network.

I need to define the method
of IP-address assignment.
In this example, I did NOT use
DHCP, but assigned a pool of
IP-addresses not yet used on
the local network segment.
NOTE: I use as IP-address the
SAME subnet (192.168.1.x)
as for my Network card !
The reminder, that you need to
assign a permission to the
Users, which are allowed to
connect via RAS
Check, that the TCP/IP
protocol is configured for
routing, that IP Forwarding is
enabled
.

To test you setup:
- define now a connection to the Internet
- configure the connection
- make a connection to the Internet.

Then, start up RAS for Dialin(either manual startup or automatic on boot).
Wait now for an incoming call.

2) Setting up a Windows95/98 Client

Install your Modem, then install
Dialup Networking (DUN)
(I prefer now to always use
the DUN 1.2 Upgrade and
install it, even if I do NOT
use VPN)
Define the connection to the
Windows NT RAS Server,
then configure the connection:
- you MUST logon
- define the TCP/IP settings
Since the NT RAS server is
assigning the IP-address, we
can leave all items on
"server assigned"
we are ready to connect, to dial:
define the username (and password),
as defined in the NT-system.

(I also suggest, that you logon to your
Windows Client using already this
Username and password to
identify yourself, that will avoid later
access permissions issues, when
connecting to the remote network)
To check your connection, run
WINIPCFG (type it into the RUN-menu)
and see, which IP-address has been
assigned to you.
check, with PING, that you have a
working connection to the systems on
the network cable (like: the NT server
and/or the mainframe) to ensure, that the
IP-routing / forwarding is working.


We can check the incoming connection on
the Windows NT RAS server:
Either using RAS Admin or
Dialup-Monitor, we can see
also the IP-address assigned
to the Client.
using in a DOS-box
("Command Prompt"),
IPCONFIG also displays
the IP-address assigned to
the Dialup-adapter of the
RAS server to handling the
incoming call.


Now we like to access the data on the disk of the NT4 RAS server and on
the disk of the NT4 server, so we look into Network Neighborhood:

But Network Neighborhood shows
only "Entire Network" and
double-clicking that brings up
the famous message:
"Unable to browse the Network"
Your system could not find
any Browse-master !
Trying it via FIND/COMPUTER
doe also not locate any
system on the network.


I have not found anywhere a clear explanation for this behavior, so I worked out for myself the following reasoning (if I am wrong, please correct me):
The systems on the local Ethernet network work out between themselves the election of the Browse-Master (which should be in my case the NT server), but this automatic selection and the participation to the Browse-Master database is NOT automatically available for other network connections, like the RAS clients.
To make the Workgroup (and its BrowseMaster) available to other network segments, the workgroup concept is enhanced: Systems are not anymore working out itself, who is a member of the workgroup, but register themselves at a predefined system using a special database, which then can also be queried for information. On Microsoft networks, this is the:
"
Windows Internet Name Service (WINS)",
which can ONLY be installed and run on a Windows NT
SERVER
(not on Windows 95 / 98 or on a Windows NT workstation).

Installation of WINS on
Windows NT server:
On the Windows NT Server,
add as additional Service the
Windows Internet Name Service
Here is the purpose of WINS,
as defined by Microsoft:
"Dynamic name registration and
resolution service that maps
NetBIOS computer names to
IP addresses
"
There is then a WINS manager
in the Administrative Tools.
But what I have read about WINS,
it is fairly much "maintenance free",
no need to configure/setup.


Configure the Windows NT RAS Dialin
system for WINS
On the NT RAS system,
configure now the TCP/IP to include
the definition of a WINS-server
(in this case: the IP-address of the
NT server).
(there seem to be other methods,
like using DNS or LMHOSTS,
which I still need to check out).


When we now connect (dialin) on the Windows95 / 98 client:

WINIFCFG show now also the
address of the WINS server.
The Network Neighborhood allows
now the access to the shared resources
on the local area network (LAN).


3) Access from the LAN to the disk of the Remote Client

A question, sometimes asked: can the Remote Client share its disk ?

On the Windows95 / NT4 client,
install File-and-Print sharing .
You MUST share SOMETHING !


On the systems on the Local area Network:
The RAS Client did NOT show up
in the Network Neighborhood of the
LAN systems, but it can be located via
FIND/COMPUTER and then accessed.
NT4 RAS as VPN TCP/IP - Dialin to a network/mainframe

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