A workgroup that doesn't work

[JohnE]

I have a desktop PC which can boot up into either Windows XP Home or Win2k Professional. My laptop PC runs only Windows XP Home. In all 3 OS's I've set up a commonly named workgroup so that the 2 machines can always see each other, regardless of which OS I'm running on the desktop machine. This has worked perfectly well for years and is still working if I run Win2k on my desktop PC. However, if I switch to Windows XP on the desktop machine something strange happens.

When XP is running on the desktop PC, the desktop machine can see all the shared folders on my laptop - but the laptop can no longer map to the shared folders on the desktop machine. Of course, I've tried rebooting numerous times, without success.

Out of desperation, I tried opening "My Network Places" on the laptop machine, then clicking on "View Workgroup Computers". I just wanted to know if the laptop could even see the other physical machine, let alone its shared folders. However, any attempt to view the workgroup computers produces the message "You do not have the correct access permissions to use this resource - Contact your system administrator."

I was under the impression that workgroups don't have an administrator. What can have gone wrong?

[vee_ess]

You may have disabled File Sharing.

[JohnE]

I discovered a bit more information since the last post......

Desktop machine with Windows XP running:
IP address is set to 192.168.0.1
Subnet Mask is 255.255.255.0
Default Gateway is 192.168.0.1
(it needs to be set up like this to allow internet sharing).

Desktop machine with Windows 2000 running:
IP address is set to 169.254.17.172
Subnet Mask is 255.255.0.0
Default Gateway is unallocated
(I never share my internet connection from the Win2K machine).

In the dim & distant past I tried setting them both to the first setting but I could never get it to work.

Laptop machine (XP Running)
IP allocation is set to "Obtain an IP address automatically"

With the above settings, it used to be the case that the laptop would automatically configure it's IP address to the appropriate range, depending upon which OS was currently running on the other machine (192.168.X.X if it was XP, 169.254.X.X if it was Win2k). However, the laptop machine is now being permanently assigned 169.254.142.117 in both cases (even though it's still set to configure automatically).

I don't know if that's the cause of the problem - but that's definitely different from that way it was before.

[JohnE]

Okay - by doing a few experiments I've discovered a bit more.....

When booting up the desktop machine....
XP seems to detect something called a network bridge, which is not detected during a Win2k boot up.

If networking is enabled via the network bridge, IP addresses are correctly assigned to/by the laptop regardless of which OS is currently running on the other machine (i.e. 192.168.X.X or 169.254.X.X, as appropriate). In this condition, internet sharing works (if both machines are running XP) but I have my original problem (laptop cannot see the desktop's shared folders).

If I disable the network bridge, the laptop gets assigned the wrong IP address and no networking works at all.

Conversely, if I set all machines to "Obtain an IP address automatically" file sharing works perfectly, but not internet sharing.

However, I'm certain that this all used to work correctly.

Tell us a little more about your network setup. Are all the PC's connected to a router?

[Jason425]

maybe you could do the "internet connection sharing" wizard

[JohnE]

Originally Posted by Travis

Tell us a little more about your network setup. Are all the PC's connected to a router?

No Travis. There are just 2 PC's connected by a crossover cable (one of the PC's can dual boot though - hence the 3 operating systems). Each machine has 2 x network interfaces, a 10/100 base-T LAN and a firewire port (which Windows seems to count as a network connection). I don't use the firewire ports for anything but when XP is running, it seems to "bridge" it to the LAN connector using that network bridge thingy.

Originally Posted by Jason425

maybe you could do the "internet connection sharing" wizard

I've tried the "Network Setup Wizard" which includes internet connection sharing.... Is that what you mean or is there a separate wizard for internet conection sharing?

As far as I understand, for internet connection sharing to work, the "host" machine (the one that connects to the internet) must have an IP address of 192.168.0.1. If I set my IP address to that setting, internet connection sharing works, so that isn't really the problem. The problem is that, for some reason, when the IP address is set to that value, the laptop machine becomes unable to see the desktop machine's shared folders.

I still have a sneaking feeling that the network bridge is at the bottom of these problems. Whatever this bridge thing is, it doesn't seem to get recongnised by Windows 2000 - and under Windows 2000, my file sharing all seems to work.

ok, you just dumped a ton of misc information. here's my take:

Originally Posted by JohnE

Desktop machine with Windows XP running:
IP address is set to 192.168.0.1
Subnet Mask is 255.255.255.0
Default Gateway is 192.168.0.1

Desktop machine with Windows 2000 running:
IP address is set to 169.254.17.172
Subnet Mask is 255.255.0.0
Default Gateway is unallocated

(192.168.X.X if it was XP, 169.254.X.X if it was Win2k). However, the laptop machine is now being permanently assigned 169.254.142.117 in both cases (even though it's still set to configure automatically).

the RFC1918 states the only usable private network address ranges. 169.254.*.* is not a valid private ip address. there is some sort of conflict and dhcp is handing your laptop [and 2k laptop] a bunk ip. microsoft's dhcp service is notorious for giving out this address when another cannot be resolved by the dhcp process.

i believe that any 169.254.*.* will result in either no connection to the internet (since it is unroutable) or that you'll never connect to the 192.168.0.* network (and thus never showing the other computers files). theres no way a 192.168.0.* network can talk to 169.254.*.* without NAT. so basically you gotta fix your ip addresses, son. try going static and using real private ip's!!

[JohnE]

Let me just clarify something....

Let's just leave Win2k out of it temporarily and concentrate on the scenario where both machines are running XP.

The problem seems to be that file sharing won't work through the network bridge. With the network bridge enabled, both machines get assigned addresses in the range 192.168.X.X. - and with this setting, internet sharing works but not file sharing.

Alternatively, if the network bridge is disabled, both machines get assigned addresses in the range 169.254.X.X .... With this setting, file sharing works but not internet sharing.

There doesn't seem to be a setting (or, at least, not an "automatic" setting) where everything works - and yet, it did work before!

I suspect that if I disable the network bridge and assign static addresses in the range 192.168.X.X everything will work - except that networking to Windows 2000 will then stop working! Anyway, I'll try that later and let you know how I get on.

[JohnE]

Okay - here's the bottom line.....

Desktop machine is set to a static address of 192.168.0.1

Laptop is now set to a static address of 192.168.0.2

If "network bridge" is enabled, internet sharing works but file sharing doesn't. If network bridge is disabled, file sharing works but internet sharing doesn't.

How did this work before then? I'm completely baffled...!