Connecting two subnets with a multihomed Win2K box

  • Thread starter Thread starter Andy
  • Start date Start date
A

Andy

Hi all!

I'm feeling like a big schmuck... I've been trying to get
this thing working for a few hours, but haven't quite had
any luck yet.

The network looks like the following:


Cable modem---> wireless router----> Computer A
192.168.2.1 192.168.2.25
|wired| (wireless)
| 192.168.3.1
Computer C (wired)
192.168.2.13 |
Computer B
192.168.3.7


(If the formatting above gets messed up: Computer C is
hooked up to the wired side of a wireless router. Computer
A hooks up wirelessly to the wireless router. Computer A
also has an ethernet card connected via a switch to
another subnet, containing Computer B.)

Both network segments work OK independently. That is,
computer A can access the internet and Computer C without
any trouble. (Computer C can also access computer A
without any trouble.) Computer B can access computer A and
vice versa.

Computers A and B are both running Win2K Pro... can't
quite bridge the connections as easily as with WinXP. IP
Routing is enabled with the registry key on computer A.

Route print on computer A brings up the following:

===========================================================
Interface List
0x1 ........................... MS TCP Loopback interface
0x2 ...00 50 bf 21 00 51 ...... Realtek RTL8139/810x
Family Fast Ethernet NIC

0x3 ...00 e0 98 be 31 ca ...... TNET1130
===========================================================
Active Routes:
Network Destination Netmask Gateway Interface Metric
0.0.0.0 0.0.0.0 192.168.2.1 192.168.2.25 1
127.0.0.0 255.0.0.0 127.0.0.1 127.0.0.1 1
192.168.2.13 255.255.255.255 192.168.2.1 192.168.2.25 1
(Added by me.)
192.168.2.25 255.255.255.255 127.0.0.1 127.0.0.1 1
192.168.2.255 255.255.255.255 192.168.2.25 192.168.2.25 1
192.168.3.0 255.255.255.0 192.168.3.1 192.168.3.1 1
192.168.3.1 255.255.255.255 127.0.0.1 127.0.0.1 1
192.168.3.255 255.255.255.255 192.168.3.1 192.168.3.1 1
224.0.0.0 224.0.0.0 192.168.2.25 192.168.2.25 1
224.0.0.0 224.0.0.0 192.168.3.1 192.168.3.1 1
255.255.255.255 255.255.255.255 192.168.3.1 192.168.3.1 1
Default Gateway: 192.168.2.1
===========================================================
Persistent Routes:
None

An ipconfig /all on computer A gives:

Windows 2000 IP Configuration

Host Name . . . . . . . . . . . . : compa
Primary DNS Suffix . . . . . . . :
Node Type . . . . . . . . . . . . : Mixed
IP Routing Enabled. . . . . . . . : Yes
WINS Proxy Enabled. . . . . . . . : No

Ethernet adapter Local Area Connection 2:

Connection-specific DNS Suffix . :
Description . . . . . . . . . . . : 802.11g Wireless PCI
Card
Physical Address. . . . . . . . . : (snip)
DHCP Enabled. . . . . . . . . . . : Yes
Autoconfiguration Enabled . . . . : Yes
IP Address. . . . . . . . . . . . : 192.168.2.25
Subnet Mask . . . . . . . . . . . : 255.255.255.0
Default Gateway . . . . . . . . . : 192.168.2.1
DHCP Server . . . . . . . . . . . : 192.168.2.1
DNS Servers . . . . . . . . . . . : 192.168.2.1
Lease Obtained. . . . . . . . . . : Wednesday, July 28,
2004 11:39:31 A

Lease Expires . . . . . . . . . . : Wednesday, August 11,
2004 11:39:31
AM

Ethernet adapter Local Area Connection:

Connection-specific DNS Suffix . :
Description . . . . . . . . . . . : Realtek RTL8139/810x
Family Fast Ethernet NIC
Physical Address. . . . . . . . . : (snip)
DHCP Enabled. . . . . . . . . . . : No
IP Address. . . . . . . . . . . . : 192.168.3.1
Subnet Mask . . . . . . . . . . . : 255.255.255.0
Default Gateway . . . . . . . . . :
DNS Servers . . . . . . . . . . . :

A traceroute from computer B to 192.168.2.13 gets stuck
after hitting computer A (192.168.3.1).

Ideally, what I want to do is to allow computer C to
access an SMB share on computer B.

*Whew!* I've played around with route.exe but haven't
gotten anywhere. I can add routes, but... :\

Any help anyone might be able to provide would be grand!
I'm probably missing something so simple...

(There are a thousand easier ways to do this... am just
trying to figure out how the routing in Win2k Pro works.)

Thanks very kindly! :)

Andy
 
The issue does not lie with Win2K routing, it lies with the wireless
router. It has no idea how to get to the 192.168.3 network.

When a packet leaves computer C destined for the 192.168.3 subnet, it
does not know how to get there and therefore sends it to it's default
gateway which is the wireless router 192.168.2.1. The wireless router
needs to know where to forward packets destined for 192.168.3 subnet
otherwise it sends the packet to it's default gateway which is most
likely the cable modem and thus the packet gets lost.

Put a static route on the wireless router that says:

For any packets destined for 192.168.3 subnet, send them to 192.168.2.25.

That should do the trick.

Mike.
 
Thanks, kindly Mike! :)

Andy
-----Original Message-----
The issue does not lie with Win2K routing, it lies with the wireless
router. It has no idea how to get to the 192.168.3 network.

When a packet leaves computer C destined for the 192.168.3 subnet, it
does not know how to get there and therefore sends it to it's default
gateway which is the wireless router 192.168.2.1. The wireless router
needs to know where to forward packets destined for 192.168.3 subnet
otherwise it sends the packet to it's default gateway which is most
likely the cable modem and thus the packet gets lost.

Put a static route on the wireless router that says:

For any packets destined for 192.168.3 subnet, send them to 192.168.2.25.

That should do the trick.

Mike.


.
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