Using PicLan with RAS and PPTP
January 20, 1998
A number of PicLan customers have asked for assistance in configuring
PicLan for use with dial-up network environments. This article discusses
two test configurations that were assembled at Modular Software.
The Test Configuration
Test System Configuration
The test configuration consisted of a production Windows NT server with
the following software loaded:
Windows NT 4.0 Server
The test client was a Windows 95 system running:
Service Pack 3
Routing and RAS accessory package
Windows 95 original production release (not an OSR release)
All of the upgrade packs are available from Microsoft on the Web or CD.
Dial-up networking upgrade version 1.2
Modems and Internet Connections
For RAS testing, the Windows NT server had an internal Boca 28.8 modem
installed on COM3 using IRQ5. The Windows 95 client had an Eiger
PCMCIA 28.8 modem installed using vendor supplied modem drivers.
For PPTP testing, the Windows NT server had a permanent routed internet
connection via an ISDN modem to a local ISP. The Windows 95 client
dialed up a standard ISP account using PPP and dial-up networking.
General Network Configuration
Configuring Network Addresses and Frame Types
In order to use RAS with PicLan, you must configure the Pick host system
and the RAS server's network interface to use IPX routers. This means
that you must assign a specific IPX network address to the Pick host system
and to the Windows NT network adapter.
On the Pick host system, you must answer "yes" to "IPX routers" and
supply a frame type and network address. If you do not otherwise
care which address you use, you should enter 802.2 as the frame type and
00000001 as the network number. If you have other routers (such as
Novell servers), you should enter the frame type and network number that
they have allocated to your local network segment. If you are running
Windows for Workgroups clients, you may be forced to use Ethernet-II frame
IPX packets instead of 802.2.
On the Windows NT RAS system, you must configure the IPX protocol to
use the same frame type and network address that you configured on the
Pick host system. You enter these values in Control Panel | Network
| Protocols | IPX/SPX | Properties for the network adapter that is connected
to your Pick host system.
RAS connnections are inherently slower than local network connections and
because of this you should lengthen the timeout values that PicLan uses.
On the Pick host, you set timeouts in the hardware setup screen. With
RAS connections, you should set the timeout value to 3 seconds (3000 milliseconds).
If you do not setup the timeout values to a longer value, PicLan will still
operate, but may generate an excessive number of retries. This does
not generally hurt operation, but may degrage performance.
On the client workstation, you set timeouts in the PL-CFG.INI file.
Again, you should set the timeout to 3000 milliseconds. The PL_SETUP
program will set this value for you if you select "dial up connection"
on the first page.
In order for the Windows NT system to act as a RAS (Remove Access Services)
server, you must install the "Routing and RAS" upgrade package from Microsoft.
The existing RAS server that is included in Windows NT 4.0 Server also
functions, but is more difficult to install and configure. The existing
RAS server that is included in Windows NT 4.0 Workstation may or may not
provide PicLan access.
Windows NT Workstation does not include the RIP for IPX/SPX service.
RIP is the routing protocol that IPX uses to interconnect networks. Without
RIP, it is unknown whether RAS will route IPX packets from the dial-up
circuit to the local network. This paper does not imply that this
configuration does not work, only that it has not been tested at Modular
After you install RAS (the Routing and RAS accessory pack), you must configure
the following elements:
Before you configure RAS, you must install and configure the Modem drivers
for your modems. You do this in Control Panel | Modems.
Routing and RAS Properties
In Control Panel | Network | Services | Routing and Remote Access Services
| Properties you must configure each modem that RAS is to use. Use
the ADD button to add each modem that is to be used by RAS. This
single screen is used to configure both dial-in and dial-out modems. This
example configures dial-in (receive calls) modems.
For each modem uses as a RAS Server, you should check "Receive calls
as a RAS server" under configure port usage.
After you have configured each modem, you then must configure the overall
network setup for RAS services. This is done by selecting the "Network"
button, which brings up the "Network Configuration" dialog box. For
PicLan use, you must check the "Server Settings" IPX box. After checking
this box, click on "Configure" for IPX networks and select "Allow remote
IPX clients to access entire network", and "Allocate nework numbers automatically".
You should not check "Assign same network number to all clients" or "Allow
client to request a network address".
You can also configure TCP/IP and NETBEUI access over RAS, but this
is not necessary for PicLan access.
Setting up a Dial-Up Account
Once RAS is setup to accept calls, you must configure a Windows NT login
account with dial-up priviledges. You should always assign a passwork
to dial-up accounts. It is this dial-up account name and passwork
that the Windows 95 client uses to gain access to the network.
Configuring Windows 95 Dial-Up Networking
You configure Windows 95 dial-up networking by installing a modem and by
clicking on "Add New Connection" in dial-up networking. You then
enter a connection name and phone number. Under network settings,
you must specify that you wish to use IPX as a protocol on dial-up.
The Windows 95 dial-up networking then proceeds normally.
When You Connect using Dial-Up Networking into RAS
When the Windows 95 system dials the RAS telephone number, the Windows
NT Server will answer the call and request a user name and password over
PPP (Point to Point Protocol). After the user is authenticated (the
account name and password is verified), the Windows 95 client system will
be assigned an IPX network address. At this point the Windows 95
system should be able to run standard PicLan client programs like PLTW,
PL-STATW, etc. and access any Pick host system on the network.
Configuring PPTP allows you to "tunnel" IPX over IP connections. This can
be used to access local IPX services from a remote system connected to
Adding PPTP to Windows NT
You must first add the PPTP protocol to the Windows NT network layer. You
do this with Control Panel | Network | Protocols | Add. When you
add PPTP to the Windows NT network layer, you specify the number of virtual
circuits that you wish to support. Each client that will simultaniously
access your network over PPTP requires a virtual circuit.
Adding PPTP to Windows 95
In order to dial-up the PPTP connection from Windows 95, the Windows 95
system must have an existing internet account and dial-up software installed.
After the internet software is installed, dial-up network is used to make
a new connection using a Virtual Private Network. Instead of supplying
a phone number, you supply the IP address of your PPTP server.
It can be confusing deciding which IP address to use with the PPTP
server. In our test case at Modular Software, the PPTP server was
running on the same system as our ISDN internet connection was connected
to. In this case, you use the IP address that is associated with
the ISDN connection and not one of the IP addresses associated with the
LAN adapters installed in the same system. Microsoft is very unclear
in this area, so some experimentation may be required.
When you configure PPTP in dial-up networking, you must specify IPX as
a requested protocol. After the PPTP connection is established, you
should be able to access IPX network resources including PicLan servers.
PicLan performance over a RAS connection will always be worse (and better)
than a direct modem connection would be into the Pick host system. In general,
you should get good overall throughput equal to at least half of the dial-up
baud rate unless your telephone connection is particularily bad.
The one area that you will notice perforance problems is in echo delay.
You should expect 1/3 to 2/3 of a second delay in seeing echo characters
from the Pick host. There is little that can be done about this delay
which is caused by latency in building packets over the modem.
PPTP performance over the internet is at the mercy of your internet connections
and internet packet path. If you have a short path from your client
to your host network (such as exists when you use the same ISP for both
sites), then the performance for PPTP will be only a slight amount worse
than a direct RAS connection. If your internet path is longer and/or
the connections and internet is busy then you may start to experience 3
to 10 second echo delays.
Our testing of PPTP performance involved our local internet connection
through Pursuit Internet | PacBell Internet | IBM Global Internet Services
on the server end and AT&T Worldnet dial-up access via AT&T's 800
number POP on the client side. In this environment there were about
15 internet hops between the client and the server and response times varied
from 2 to 8 seconds for echo delay. While this is "poor" from a performance
point of view, it is amazing that it works at all and overall the connections
were quite reliable. Our PPTP tests also had us mapping a number
of NetWare drives over the internet as well. NetWare directory operation
usually took 20 to 40 seconds and file copies could take several minutes
for 100K files. It should be noted that Windows NT file system access
took about the same amount of time.
There are many other possible configurations that should work with PicLan.
We have heard that the following configurations can also
Send Us Your Experiences
If you have tried these configurations, email your experiences to firstname.lastname@example.org
so that we can pass them on to others.
Windows NT workstation RAS
Windows 95 "Plus Pack" dial-up server