The Strange and Wonderful Master Browser

[Bobby]

This comes from another thread, but I hope it will help people understand peer-to-peer networks and how to configure them.

The question to be asked is: How does one PC on a network find another PC?

Back in the old days, they did it by shouting (more politely called broadcasting). If PC "A" wanted to find PC "B" it would issue a broadcast that went everywhere on the network, saying "Hey "B" - where are you?" "B" (if there) would respond with its real address (called a MAC address or layer 2 address - note: NOT an IP address) and from then on "A" could talk to "B" directly.

The problem was that all this shouting could slow down a large network. To fix this problem, the Master Browser was born. The MB is a task running in the network on a single PC that understands the topology (i.e. connections and PCs) and keeps that knowledge up to date. When a PC wants to find another PC, it now contacts the MB directly and asks, and the MB responds with the MAC address. No broadcasting.

The next question is: Where is the MB?

In a client-server network (i.e. one having a real Microsoft (or other) server), the server is always the MB.

But what about a peer-to-peer network (our kind) which has no specifically defined server? In order to handle that, the MB is dynamically assigned to any PC in the network and it can change at any time. This process is called "election" and can be initiated for various reasons, including a PC joining or leaving the network.

The problem is that sometimes the MB ends up where you don't want it. I have seen networks where the slowest PC became the MB just by chance. During election, the network will not run correctly, although pre-established relationships between two PCs will still be OK.

So, two things: First, you can force one PC to always be the MB. You do this by turning off the browser service on all PCs except the want you want.

To stop the browser process, go to Start / Control Panel (Classic View if necessary) / Administrative Tools. Once there, click on Services and then look down the list for Computer Browser. Right click on it, go to Properties. If the Service Status is Started, Stop it. Then change the Startup Type to Disabled.

Another good thing to do is to find out which PC is the MB by going to a DOS (command prompt) and typing the command:

nbtstat -n

If the resulting list of "stuff" contains one with the label __MSBROWSE__ then that particular PC is the MB. If you have more than one PC in your network that thinks IT is the MB, you have some kind of problem - and most problems of this nature are due to improperly configured firewalls.

Lots more if anybody wants to get deeper. Just ask a question!

Bob

[Steve Grisetti]

I know nothing about this world, Bob. To me it's as mysterious as the internet -- or the interstate highway system, for that matter. I just get on and drive!

But thanks for shedding some light on this shadowy, strange world.

[VernonRobinson]

Bob,
Thanks for the explanation. It was clear and concise. Like the prior poster, I have one machine that won't let me look at a shared drive. I ran the nbtstat as suggested, but do not see the master browser. What am I not understanding?

Thanks,
-Vernon

nbtstat_Enterprise_PC.jpg

[Bobby]

OK Vernon. Well, that shows a PC called Enterprise in a workgroup called Workgroup. That sounds pretty much like a default situation. But the MB is obviously not on that PC, and since it hasn't elected ITSELF as the MB, it thinks there is another PC in the network that IS the MB. So far so good.

What versions of Windows are on the various PCs? I ask because in XP all the layer 2 functions (NETBIOS) functions were subsumed under TCP/IP and thus controlled by firewalls. And what firewalls do you have running (Norton, McAfee, etc.)

Bob

[jackfalbey]

Vernon, I had a similar problem where the MB (Dell 8400) could share with the laptop and the workstation, and vice-versa, but the laptop and workstation could not share between each other. The fix was that each computer had a slightly different IP (the MB ended in .100, the laptop in .101, and the workstation in .103 (which makes me wonder where .102 is, but that's a separate issue )) and after adding each one to the firewall's Trusted Zone on each computer, they can now all share with each other.

By the way, thanks again Bob for bringing up the networking topic; you helped me get mine set up quickly and troubleshoot it without any prior experience on my part. Your Moderator title is well-deserved.

[Bobby]

Thanks, Jack. Yes, those firewalls can sometimes be difficult to configure.

I hate to say this, because it is the popular culture these days to claim otherwise, but I like Norton. The Norton Internet Security 2008 is an excellent package. They have improved performance and eliminated almost all communication with the user (who didn't know how to answer those firewall questions anyhow). Every single one of my clients who uses Norton has had ZERO problems.

The Norton firewall configures networks by MAC address rather than IP range now. So you just have to identify a particular adapter (LAN or wireless, etc.) and say that the network associated with that is Trusted. Then all works fine within that network.

And, yes, it's nice to be a Moderator again. I was one of the original guys around here (on Chuck and Steve's request as I recall), but last year I dropped out for the entire second half of the year running for office. Glad to be "back"!!!!

Bob

[VernonRobinson]

Bob,
So as to gain perfect clarity, I need to go to each machine and only the one that is Master Browser will have the appropriate tag. Is that correct? It seems that a machine called OPC01 is the Master Browser.

Also, I think each machine in my WorkGroup runs Windows XP except for a development server that is not running in a domain that runs Windows 2003 Server Enterprise Edition (OPC01) and a laptop that runs Vista Ultimate. The problem that I have is that on the Vista machine, I have some directories that are shared and seem to work ok. But I tried to share the C-Drive and get the error shown in image 1 below. Also, here is the results of nbtstat on the Vista machine called Vaio18. As I said before, the other shares seem to work fine. ONly the highlighted share does not seem to work.

Enterprise to Vaio.jpg

Vaio18.jpg

[VernonRobinson]

Vernon, I had a similar problem where the MB (Dell 8400) could share with the laptop and the workstation, and vice-versa, but the laptop and workstation could not share between each other. The fix was that each computer had a slightly different IP (the MB ended in .100, the laptop in .101, and the workstation in .103 (which makes me wonder where .102 is, but that's a separate issue )) and after adding each one to the firewall's Trusted Zone on each computer, they can now all share with each other.

By the way, thanks again Bob for bringing up the networking topic; you helped me get mine set up quickly and troubleshoot it without any prior experience on my part. Your Moderator title is well-deserved.

Jack,
Thanks for the feedback. My situation is slightly different in that most of the shares work between the two machines (so I rationalize that the communications is good), but there is 1 share that does not work which has me puzzled.

Concerning the missing IP address, it could be a number of things. The numbers are dynamically assigned over a range and they have an expiration date unless you explicitly tell it not to expire. One of the machines or most likely your router is running DHCP and assigning the IP addresses for those machines on your network.

The machine that had 102 may have had its lease expire or someone could have temporarily signed on to the network (e.g. using a laptop) and took that slot. It is nothing usually to worry about.

-Vernon

[Bobby]

Bob,
So as to gain perfect clarity, I need to go to each machine and only the one that is Master Browser will have the appropriate tag. Is that correct? It seems that a machine called OPC01 is the Master Browser.

Also, I think each machine in my WorkGroup runs Windows XP except for a development server that is not running in a domain that runs Windows 2003 Server Enterprise Edition (OPC01) and a laptop that runs Vista Ultimate.

All of my prior comments were in relation to peer-to-peer networks. You have a client-server network, with a real MS server if it is running Server Enterprise Edition. All of your PCs should thus be in a domain, not in a workgroup.

But, yes, only one PC will show as the MB and in your case it is correctly on the server. There is no dynamic election in a client-server environment.

I don't have any experience with Vista machines in a client-server environment. Vista Ultimate supports domains, as oposed to the Home editions which does not. But Vista is really kookie on shares, especially of an entire drive. Can you PING the VAIO from the server? Can you share just a folder on the VAIO?

Bob

[Bobby]

...Concerning the missing IP address, it could be a number of things. The numbers are dynamically assigned over a range and they have an expiration date unless you explicitly tell it not to expire. One of the machines or most likely your router is running DHCP and assigning the IP addresses for those machines on your network...

Yes, IP addresses are always dynamically assigned via DHCP unless manually overridden. That bears no relationship to file sharing except that a firewall may block a specific IP address. Generally although there is in fact a lease expiration time on DHCP leases, in practicality that never happens are the same address is always re-assigned again to the same PC.

But the overriding point is that you shouldn't have to configure your firewall with individual addresses. Most can accept a range of addresses or in the case of Norton a MAC address for the entire network. If you have to reconfigure your firewall every time an IP address changes, that is mucho work.

Bob

[VernonRobinson]

Bob,
As I stated in a prior post, the Windows 2003 Server is NOT part of a domain. It is part of the workgroup called WorkGroup. I am thinking about deleting the share on the Vaio and trying it again. Too many things are working correctly, just something a little bit askew with this one share. Any other ideas?

-Vernon

[Bobby]

Bob,
As I stated in a prior post, the Windows 2003 Server is NOT part of a domain. It is part of the workgroup called WorkGroup. I am thinking about deleting the share on the Vaio and trying it again. Too many things are working correctly, just something a little bit askew with this one share. Any other ideas?

-Vernon

My server experience is not too extensive because here at the beach there aren't any servers! Most of my clients are small business with peer networks. But I thought that a server is not part of a domain - it DEFINES a domain. And I am uncertain about whether a server can in fact be part of a workgroup or not.

But your point is well taken. It seems to be working except in this particular instance. Make sure the server can PING the VAIO and check / redo the network shares on the VAIO. I would also try the test of sharing just a folder rather than the entire C drive due to Vista's fussiness about shares and security.

Bob

[VernonRobinson]

Bob,
Thanks for hanging in there. A server can define a domain, be part of a domain, or in my case be part of a workgroup. But the Server is a distraction to my original conversation. The problem is between two PCs that are part of the same WorkGroup. In this case the Vaio and Enterprise. Any other ideas for consideration?

-Vernon

[Bobby]

1) Can you PING the server from the VAIO and vice versa?

2) re-do the Vista network shares

3) try sharing only a single folder and not the entire hard drive

Bob

[Jayell]

Jumping in here a little late, but I was not familiar with the Master Browser .. and found your post extremely informative. I have two computers connected peer-to-peer.