multiple master browsers in domain??

[phishphreek]

C:\Documents and Settings\user>nbtstat -a server1

Local Area Connection:
Node IpAddress: [192.168.0.10] Scope Id: []

NetBIOS Remote Machine Name Table

Name Type Status
---------------------------------------------
server1 <00> UNIQUE Registered
server1 <20> UNIQUE Registered
domain <00> GROUP Registered
domain <1C> GROUP Registered
domain <1B> UNIQUE Registered
domain <1E> GROUP Registered
domain <1D> UNIQUE Registered
..__MSBROWSE__. <01> GROUP Registered

MAC Address = XX-XX-XX-XX-XX-X1


C:\Documents and Settings\user>nbtstat -a server2

Local Area Connection:
Node IpAddress: [192.168.0.10] Scope Id: []

NetBIOS Remote Machine Name Table

Name Type Status
---------------------------------------------
server2 <00> UNIQUE Registered
domain <00> GROUP Registered
domain <1C> GROUP Registered
server2 <20> UNIQUE Registered
domain <1E> GROUP Registered
domain <1D> UNIQUE Registered
..__MSBROWSE__. <01> GROUP Registered

MAC Address = XX-XX-XX-XX-XX-X2

C:\Documents and Settings\user>nbtstat -a server3

Local Area Connection:
Node IpAddress: [192.168.0.10] Scope Id: []

NetBIOS Remote Machine Name Table

Name Type Status
---------------------------------------------
server3 <00> UNIQUE Registered
domain <00> GROUP Registered
domain <1C> GROUP Registered
server3 <20> UNIQUE Registered
domain <1E> GROUP Registered

MAC Address = XX-XX-XX-XX-XX-X3

Server1 is the "master" browser and is supposed to be the "PDC" if there is such a thing in Active Directory.

server2 is a backup browser that participates in browser elections if the master browser is down.... a "BDC" if there is such a thing in Active Directory.

server3 is a backup browser that participates in browser elections if the master browser is down.... a "BDC" if there is such a thing in Active Directory.

Both server1, server2 and server 3 are on different subnets.
Server 3 doesnt' show up as master browser.

Using browser mon I have determined that server1 is the domain master browser.

According to netbios hex codes (http://jcifs.samba.org/src/docs/nbtcodes.html) both server1 and server2 are the "master browser".

I see that server1 also has a hex code of 1B which is Domain Master Browser.

<domain> 1B U Domain Master Browser
<computername> 01 U Messenger Service
<\\--__MSBROWSE__> 01 G Master Browser
<domain> 1D U Master Browser
<domain> 1 E G Browser Service Elections

None of my other 2k servers (either on the same subnet or different subnets) have a hex doce of 1D or 01 which is Master Browser.

Why would server1 and server 2 both show up as master browser?

I thought that there was only allowed to be one master browser. The master browser is also the domain master browser.

What am I missing?!

[gunit0072003]

Are any of the 2000 servers configured as domain controllers?
Or just stand alone servers

[phishphreek]

Are any of the 2000 servers configured as domain controllers?

All three above in my example are domain controllers. I have a couple more that I did not include that look exactly like server3 in my example above.

[rapier57]

[/quote]
Server1 is the "master" browser and is supposed to be the "PDC" if there is such a thing in Active Directory.
[/quote]

In mixed mode, yes there is a PDC emulator and works almost just like the NT 4.x version.

[/quote]
Both server1, server2 and server 3 are on different subnets.
Server 3 doesnt' show up as master browser.
[/quote]

This is the key to what you are seeing. There will be a master browser for each subnet. Your "PDC" will be the master browser for that subnet and the domain. You will want to make sure that it wins elections at all times and that the server will not give up its name on the network (currently patched version should not allow that).

An election will be performed on the subnets and a server or workstation will become the browser master for that subnet.


[/quote]
Why would server1 and server 2 both show up as master browser?

I thought that there was only allowed to be one master browser. The master browser is also the domain master browser.
[/quote]

They are not on the same subnet, and, in a way, their master browser roles are very different.

[phishphreek]

Ok, so there can be only one Domain Master Browser per domain.

But... there can be only one master browser per subnet.

Gotcha.

Thanks for clearing that up for me.

I just found a good explanation on m$'s site.
http://support.microsoft.com/default...NoWebContent=1

[thehorse13]

One more quick addition to this one. In a true AD environment, there is no PDC/BDC architecture. A Global Catalog is used and is replicated across all AD controllers on your network. As it was so cleary pointed out by rapier57, elections for master browser status will take place on each subnet. The status is handed out based on Microsoft's class system which has AD controllers on the top and I believe W95 workstations at the bottom. My memory is sketchy on the exact order but I'm sure one of our sharp MS admins can give the exact order.

Rapier57. Very nice response.

--TH13

[phishphreek]

The reason I was referring to them as PDC and BDC is because I still have some servers that are running NT4. They are being replaced right now... but I have the setup that rapier57 referred to which is the mixed mode.

As soon as I replace the last NT4 box, then I can switch it over.

[rapier57]

You can go to native mode any time _after_ you have removed the last NT4.x-based DC in the network. But, you also want to look at the structure of AD and clean up any ophaned objects prior to flipping the switch. It is a one way thing.

[mohaughn]

Another article about browser master in AD environments.
http://support.microsoft.com/default...b;en-us;188001

Even if you are native mode AD, you still have to run the PDC emulator if you have NT4.0 and earlier clients/servers in your network. You can only shutdown the PDC FSMO if all clients are Win2k or higher. Also should be noted that not all AD "controllers" house the global catalog server. For instance we have over 45 Win2k domain controllers, but only 10 global catalog servers.

[thehorse13]

mohaughn is correct, I should have noted that this is how we deal with the Global Catalog. As he pointed out, you can configure how the Global Catalog is replicated and who houses it.