WinNT & ppp - problem s routovanim
Rudisar Ladislav
rudisar at faf.cuni.cz
Sat Jan 13 14:36:10 CET 1996
Jiz jsem to tusim do konference o Windows NT (winnt-l) posilal, takze
jeste jednou. (Jinak http://emwac.faf.cuni.cz Microsoft Knowledge Base -
heslo RIP).
DOCUMENT:Q121877 09-JAN-1996 [winnt]
TITLE :Using RAS for Routing of IP Packets
PRODUCT :Microsoft Windows NT
PROD/VER:3.50 3.51
OPER/SYS:WINDOWS
KEYWORDS:kbnetwork kbfasttip
----------------------------------------------------------------------
The information in this article applies to:
- Microsoft Windows NT Workstation versions 3.5 and 3.51
- Microsoft Windows NT Server version 3.5 and 3.51
----------------------------------------------------------------------
SUMMARY
=======
The first part of this article covers the following supported features:
- Features and limitations of Windows NT RAS routing.
- Conditions to be met for Windows NT RAS routing to work.
- Configuring a Windows NT RAS client to route over a RAS link.
- Troubleshooting a Supported RAS Routing configuration.
The second part of this article covers the following unsupported
features:
- Windows NT to Windows NT RAS routing (unsupported, but possible).
- Diagram of Windows NT to Windows NT RAS routing (with two subnets
only).
- Summary table of Windows NT to Windows NT RAS routing configuration.
- Configuring Windows NT to Windows NT routing.
MORE INFORMATION
================
Features and Limitations of RAS Routing
---------------------------------------
The Windows NT 3.5 Remote Access Services (RAS) client has a new feature
that allows it to function as a router between two different networks.
However, it supports only local and non-subnetted routing; there is no
support for interrouting protocols such as RIP or OSPF. The ROUTE utility
can be used to build static routes into your system's routing table.
ROUTE.EXE is installed in the %systemroot%\SYSTEM32 directory when you
install TCP/IP under Windows NT (see Windows NT version 3.1 [not 3.5]
Resource Kit, Volume 1, page 661, ISBN 1-55615-598-0).
Conditions to be Met for RAS Routing to Work
--------------------------------------------
The following conditions have to be met in order to use this new feature:
- The RAS server must be a third party PPP or SLIP server. (Windows NT
3.5
RAS is currently not designed to support LAN to LAN routing.)
- The third-party RAS server must support routing tables that can be
configured to forward packets to the LAN connected over the Windows NT
3.5 RAS client link.
- TCP/IP is the protocol on both sites.
- The IP subnet address of the local LAN is different from the IP subnet
address of the RAS connection.
- If connecting your local LAN to the Internet, your LAN must use a
registered IP address.
Configuring a Windows NT RAS Client to Route over a RAS Link
------------------------------------------------------------
If these conditions above are met, you need to configure the Windows NT
3.5
or 3.51 RAS client as follows to allow it to function as a router.
1. Configure RAS for either PPP or SLIP.
a. Run Remote Access and choose Edit.
b. Choose the Advanced button if it is displayed.
c. Choose Network.
d. Select either PPP (using TCP/IP) or SLIP for communication with the
third-party RAS server.
2. Modify the DisableOtherSrcPackets registry value that, by default, is
set to disable this functionality. DisableOtherSrcPackets is located
in
the HKEY_LOCAL_MACHINE subtree under the following subkey:
\System\CurrentControlSet\Services\RasArp\Parameters
It has a data type of REG_DWORD and can be set to 0 or 1. It controls
the routing of IP packets with an IP source address other than the IP
address of the RAS network adapter card. Set to 0, packets with source
addresses other than the IP address of the RAS adapter will be sent.
Set
to 1, packets with source addresses other than the IP address of the
RAS
adapter will not be sent. The default setting is 1.
NOTE: Page 420 of the "Windows NT 3.5 Resource Kit, Volume II"
incorrectly states that the default setting is 0.
NOTE: You must reboot your computer for this parameter to take effect.
3. Enable the IpEnableRouter value. IpEnableRouter is located in the
HKEY_LOCAL_MACHINE subtree under the following subkey:
\System\CurrentControlSet\Services\Tcpip\Parameters
It has a data type of REG_DWORD and can be set to 0 or 1. Change the
value to 1 to enable this parameter. A value of 0 disables IP
routing.
NOTE: You do not have to reboot your computer for this parameter to
take
effect.
4. The Default Gateway for the network card on the RAS client computer
should be blank.
5. The local LAN clients must set their Default Gateway to the network
card IP address of the Windows NT RAS client.
6. You must set up a static route on the third-party PPP or SLIP server
that routes traffic destined for the RAS client s local LAN through
the RAS IP address of the RAS client.
Troubleshooting a Supported RAS Routing Configuration
-----------------------------------------------------
To troubleshoot routing problems between the Windows NT RAS client and
the
third party RAS server, use Windows NT RAS Monitor on the RAS client. RAS
Monitor starts automatically when the Remote Access client is started,
unless that option was disabled in the Options menu of Remote Access.
If you ping the PPP or SLIP server from a local LAN client, you should
see
the transmit light of RAS Monitor flash four times. If so, the packets
are
being routed properly by the Windows NT RAS client and you should go back
to step 6 and ensure the third party RAS server is configured for the
correct route.
Windows NT to Windows NT Routing (Unsupported, But Possible)
------------------------------------------------------------
WARNING: The current version of Windows NT was not designed to provide
Windows NT to Windows NT routing functionality. Use the following
information with the understanding that Microsoft makes no guarantees
that
this works reliably. You cannot get support if there are problems with
this
configuration. If you have a problem, you need to reproduce the problem
under a supported configuration to get support. If the problem only
occurs
in the unsupported configuration, we recommend that you restore your
network to a supported configuration. This feature is under review and
will
be considered for inclusion in a future release.
Windows NT to Windows NT routing was successfully tested in the Microsoft
Product Support Services lab with only one subnet on each side of the RAS
link. It was not stress tested.
Configurations with more subnets on either side of the RAS link may be
possible, but the configuration becomes increasingly complex (and has not
been tested), because Windows NT 3.5 has no support for interrouting
protocols such as RIP or OSPF. Therefore, many more routes need to be
established by using the Route command on the Windows NT RAS server or by
configuring a router.
Diagram of Windows NT to Windows NT RAS Routing (with Two Subnets Only)
-----------------------------------------------------------------------
The following is a diagram of the lab setup that was tested:
NOTE: The aaa and bbb in the TCP/IP addresses represent the three decimal
digits of the first part of a regular four-part TCP/IP address. They are
used to protect you from using an actual TCP/IP network address that is
in
use on the Internet or in your company. Be sure to replace all TCP/IP
addresses in this example with your own addresses.
Single Client Server Single
Subnet--ether--NT3.5Ras-----PPP/TCP/IP-----NT3.5Ras---ether---Subnet
Subnet_A Subnet_A Subnet_B Subnet_B
aaa.180.90.1 aaa.180.90.2 bbb.8.0.1 bbb.8.0.2
Def. Gtwy: Def. Gtwy: Def. Gtwy: Def. Gtwy:
aaa.180.90.2 aaa.180.90.2 bbb.8.0.1 bbb.8.0.1
(=RAS client) (its own address!) (its own addr!) (=RAS Svr)
RAS: Subnet_C range:
bbb.88.89.1 - 2
RAS: Subnet_C RAS: Subnet_C
bbb.88.89.2 bbb.88.89.1(1st in range)
Summary Table of Windows NT to Windows NT RAS Routing Configuration
-------------------------------------------------------------------
The following table summarizes the configuration:
RAS Client RAS Server
============================ =======================================
On single subnet without On single subnet without routers
routers
Ethernet TCP/IP address Ethernet TCP/IP address
for Subnet_A for Subnet_B
RAS PPP with TCP/IP RAS PPP with TCP/IP
(not SLIP)
Decide which TCP/IP addresses to use
exclusively for a RAS Subnet_C
Check "Require Specific IP In Control Panel specify RAS server
Address" and enter address TCP/IP range of at least 2 addresses
(the 1st always owned by RAS server)
Check "Use Default Gateway
On Remote Network"
DisableOtherSrcPackets: 0 DisableOtherSrcPackets: 0
IpEnableRouter: 1 IpEnableRouter: 1
Set the local LAN clients' Set the local LAN clients'
Default Gateway to the Default Gateway to the
RAS client's Subnet_A address RAS server's Subnet_B address
(not Subnet_C!) (not Subnet_C!)
Manually add a Route to routing table
See step 6 below.
NOTE: To add the route to the RAS server's routing table, follow this
pattern when typing the Route command:
Route add <Subnet_A_Address> MASK <subnet mask> <RasClientAddress>
The following is an example with fictitious class C subnet addresses:
Route add aaa.180.90.0 MASK 255.255.255.0 bbb.88.89.2
where aaa and bbb in the TCP/IP addresses represent the three decimal
digits of the first part of a regular four-part TCP/IP address.
This command tells the RAS server to get to Subnet_A (aaa.180.90.0)
forward packets addressed to it to the RAS client (bbb.88.89.2) on
Subnet_C. The RAS client knows about Subnet_A (aaa.180.90.0)
automatically during boot up because its Ethernet card is on
Subnet_A and IpEnableRouter is enabled.
Configuring Windows NT to Windows NT Routing
--------------------------------------------
To configure Windows NT to Windows NT routing over RAS between two
single
subnets:
1. Configure the RAS server for Subnet_C TCP/IP addresses for assignment
to RAS clients.
a. On the RAS server, run Control Panel and choose Network.
b. Select Remote Access in the Installed Network Software list box.
c. Choose Configure.
d. Choose Network.
e. In the Server Settings choose Configure for TCP/IP.
f. Select the Use Static Address Pool radio button.
g. Enter a TCP/IP subnet address in the Begin and End text boxes.
These two addresses must be consecutive or in a range of several
consecutive addresses. They must not belong to the same subnet of
the local LAN, nor the RAS client's LAN. For example, bbb.88.89.1
through bbb.89.88.2 are valid addresses for the lab setup above.
The first address of this range will belong to the RAS server
so that it will end up with two IP addresses: one for
RAS and one for the Ethernet card configured in the regular
TCP/IP configuration.
2. Configure the RAS client to use TCP/IP, request a specific TCP/IP
address, and use the server's default gateway.
a. Run Remote Access and choose Edit.
b. Choose the Advanced button if it is displayed.
c. Choose Network.
d. Select PPP and check TCP/IP. Do not select SLIP for communication
with the Windows NT RAS server.
e. Choose TCP/IP Settings.
f. Choose Require Specific IP Address and enter the second IP address
in the IP range specified on the RAS server in step 1. In the
example above that would be bbb.88.89.2.
g. Then check the Use Default Gateway On Remote Network box at the
bottom.
3. On the RAS server and the RAS client, set DisableOtherSrcPackets to 0
(zero) in the Registry as described above.
NOTE: This parameter does not take effect until you reboot your
computer.
4. On the RAS server and the RAS client, set IpEnableRouter to 1
in the Registry as described above.
5. Reboot the RAS server.
6. Add the route to the RAS server as explained above in the note at
the bottom of the table above.
7. The local LAN clients of Subnet_A must set their default gateway
to the Subnet_A network card IP address of the Windows NT RAS client.
8. The local LAN clients of Subnet_B must set their default gateway
to the Subnet_B network card IP address of the Windows NT RAS server.
NOTE: A machine on Subnet_A should not call into the RAS server
on Subnet_B while the Windows NT RAS client on Subnet_A is connected
to the RAS server on Subnet_B. This can be prevented if a Subnet_C
range of only two IP addresses is specified or only one modem is
installed on the server. However, if this situation occurs, you will
get unpredictable results.
KBCategory: kbnetwork kbfasttip
KBSubcategory: ntras nthowto ntregistry
Additional reference words: point-to-point prodnt 3.50 3.51
==========================================================================
===
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SO THE FOREGOING LIMITATION MAY NOT APPLY.
Copyright Microsoft Corporation 1996.
---------------
Zdravi,
#
# Ladislav Rudisar
# European Microsoft Windows NT Academic Center (EMWAC CZ)
# URL: http://emwac.faf.cuni.cz
# Faculty of Pharmacy, Charles University
# URL: http://www.faf.cuni.cz, http://www.cuni.cz
# Heyrovskeho 1203, 500 05 Hradec Kralove
# Czech Republic
#
# tel. +42-49-5235021 l. 473
# fax +42-49-5210002
# e-mail: rudisar at faf.cuni.cz
----------
From: owner-csinfo-l[SMTP:owner-csinfo-l at EARN.CVUT.CZ]
Sent: 12. leden 1996 17:11
To: Multiple recipients of list CSINFO-L
Subject: WinNT & ppp - problem s routovanim
Dobry den.
Situace: WinNT 3.5 server v LAN s WinNT 3.51 a Win95 stanicemi. Nyni
pokus
o pripojeni na Internet pomoci vytacene ppp linky z WinNT serveru.
Spojeni
se navaze bez problemu a pak je situace takova: pocitace v ramci LAN
(vcetne toho serveru) pracuji (=situji mezi sebou) bez problemu. Ze
serveru
lze pristupovat do Internetu.
Ale: pri pokusu o pristup do Internetu ze stanice se hlasi "Host
unreachable."
Neni to absenci routovaci informace na te stanici, cili se zda, ze WinNT
server z nejakeho duvodu neroutuje mezi LAN a ppp dratem. Clovek, ktery
se
to snazi nakonfigurovat, uz nejake zkusenosti s TCP/IP ma, jde tedy dost
mozna jen o nejakou ptakovinu.
Pred zahajenim hlubsi analyzy problemu se chci zeptat, zda uz nekdo na
neco
takoveho nahodou nenarazil?
Pripadne odpovedi prosim primo na <eda at vse.cz>.
Dekuji,
Eduard Vopicka
--
"Eduard Vopicka, Computing Centre, Prague University of Economics,
W. Churchill Square 4, CZ 130 67 Prague 3" <Eduard.Vopicka at vse.cz>
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