Re: Different views of the same network...

Hello sarkiaponius,

Using my network to see all machines requires at least that you enable NetBIOS
over TCP/IP (network properties>TCP/IP>advanced>WINS>enable netbios over
TCP) on all machines and if you have multiple subnets you have to use a WINS
server in the network.

Best regards

Meinolf Weber
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> Hi,
>
> first of all I beg your pardon for my english. Also, be kind to me,
> because I'm a Windows guy: though I went to some Microsoft courses and
> I even take an official exam with success, in the end I'm a Linux guy.
>
> My problem concern browsing the network. We only have a single domain,
> with two domain controllers both running MS Windows Server 2003.
> Normally, all pc's and servers, when they browse the network with the
> usual "My Network" tool, see exactly the same network. I mean they all
> see the same hosts listed in the "My Network" window. Also, they all
> see the same workgroups (actually, there are very few hosts not inside
> the domain, but that's what we want).
>
> Recently, I could say a week ago, someone told me he could not see the
> host of a colleague. I took a look at the list of hosts he had in "My
> Network", and I realized that the list was different from the one I
> was able to see on a server I was working on at that moment.
>
> After a while, I also realized that the two list were disjoint, and
> the union of the two lists was equal to the actual content of the
> network. In other words, the network seemed to be split in two parts.
>
> But this is only true for browsing: using "search" in "My Network"
> allowed us to find the "missing" host, and any other host not listed.
> Also, shared folders are still accessible with the right permissions.
>
> Finally, I made a network hardware test. We have 5 switch, and I
> noticed that some of the hosts my colleagues can see browsing the
> network are all connected to the same switch. So I tried to disconnect
> one of this host from that switch and to connect it to another one,
> and after the obvious "refresh" of the network window... the host was
> able to see the other half of the network!
>
> My idea is that one of the switch, or maybe the network device to
> which all the 5 switch are connected (sorry, I don't know the name in
> english, but it's a Network Xtreme Summit 5i), has some problems. But
> since all these devices are managed by an external firm, I must be
> sure it's not my fault. I only administer the domain and some other
> services, not the hardware devices.
>
> A couple of years ago, we noticed something similar, and after a month
> the Summit 5i got broken and it was substituted wih a new one, and
> every problem disappeared. That's why I suspect it's its fault this
> time too.
>
> Best regards.
>

sarkiaponius <> wrote:
> On 8 Set, 15:11, Meinolf Weber [MVP-DS] <meiweb@(nospam)gmx.de> wrote:
>> Hello sarkiaponius,
>>
>> Using my network to see all machines requires at least that you
>> enable NetBIOS over TCP/IP (network
>> properties>TCP/IP>advanced>WINS>enable netbios over
>> TCP) on all machines and if you have multiple subnets you have to
>> use a WINS server in the network.
>
> We have that enabled on all hosts. Also, the topology of the network
> had never changed in the last five years, and we never had a WINS
> server, so there should not be any reason why we suddenly need it.
>
> The different lists that we see span over two different subnets,
> namely 192.168.20.255 and 192.168.21.255. I mean that the difference
> is not related to the network address. I guess some network device is
> blocking packets needed to browse the network. I know tha Summit 5i
> can work at higher levels in the TCP/IP stack, so before it hangs it
> could behave as a filter for some kind of packets.
>
> Please note that the our network is a single broadcast domain, but it
> is split into 5 collision domain by the 5 switches. Also, it is
> connected with the router by the Summit 5i. So I don't think we have
> the need for a WINS server, but I may be wrong.
>
> Many thanks anyway.
>


You have been lucky thus far. If you are going to use NetBIOS over TCP/IP,
you should *definitely* use WINS and you should *definitely* stop and
disable the computer browser service on all workstations & servers besides
the WINS box. NetBIOS is very chatty and you're running into browser
elections & conflicts. Don't worry about why it worked fine before without
WINS - the problem you are having now is precisely what WINS is designed to
avoid, and you can fix the problem easily. You can have everyone register
into the same WINS database - you don't have to have multiple ones.

Or disable it entirely for all, and don't use network places.

Here is a bit of background. The computer browser service was designed a
long time ago when networks were very simple - a few machines plugged into a
hub. The browser service and name resolution worked by broadcasting on the
wire. Computers communicated using Netbeui.

When TCP/IP became common, the browser service was modified to use
Netbios over TCP/IP instead of Netbeui. WINS was developed to allow name
resolution in a routed network (since broadcasts don't cross routers). WINS
also allows browsing across IP routers by allowing the master browsers to
communicate directly.

Switches do not work the same way as hubs. Browsing does not always work
properly on switched networks without WINS (as you have discovered).
Machines on the same switch are fine, but machines on different switches end
up in different browse lists. WINS solves the problem.


"sarkiaponius" <> wrote in message
news:ac4463ce-09c9-4464-a0ad-...
> Thanks for your kind answers and suggestions.
>
> But what makes the whole business so strange is that we definitely
> didn't change anything in the configuration of our pcs and servers for
> many months. Also, remember that simply connecting a host to a
> different switch makes it see the other half of the network. This
> cannot be related in any way to WINS or NetBIOS configuration.
>
> Anyway, your suggestions about the use of a WINS server are very
> interesting, what ever the actual problem is.
>
> Best regards.
>
> On 9 Set, 04:30, "Lanwench [MVP - Exchange]"
> <lanwe...@heybuddy.donotsendme.unsolicitedmailatya hoo.com> wrote:
>> sarkiaponius <sarkiapon...@gmail.com> wrote:
>> > On 8 Set, 15:11, Meinolf Weber [MVP-DS] <meiweb@(nospam)gmx.de> wrote:
>> >> Hello sarkiaponius,
>>
>> >> Using my network to see all machines requires at least that you
>> >> enable NetBIOS over TCP/IP (network
>> >> properties>TCP/IP>advanced>WINS>enable netbios over
>> >> TCP) on all machines and if you have multiple subnets you have to
>> >> use a WINS server in the network.
>>
>> > We have that enabled on all hosts. Also, the topology of the network
>> > had never changed in the last five years, and we never had a WINS
>> > server, so there should not be any reason why we suddenly need it.
>>
>> > The different lists that we see span over two different subnets,
>> > namely 192.168.20.255 and 192.168.21.255. I mean that the difference
>> > is not related to the network address. I guess some network device is
>> > blocking packets needed to browse the network. I know tha Summit 5i
>> > can work at higher levels in the TCP/IP stack, so before it hangs it
>> > could behave as a filter for some kind of packets.
>>
>> > Please note that the our network is a single broadcast domain, but it
>> > is split into 5 collision domain by the 5 switches. Also, it is
>> > connected with the router by the Summit 5i. So I don't think we have
>> > the need for a WINS server, but I may be wrong.
>>
>> > Many thanks anyway.
>>
>> You have been lucky thus far. If you are going to use NetBIOS over
>> TCP/IP,
>> you should *definitely* use WINS and you should *definitely* stop and
>> disable the computer browser service on all workstations & servers
>> besides
>> the WINS box. NetBIOS is very chatty and you're running into browser
>> elections & conflicts. Don't worry about why it worked fine before
>> without
>> WINS - the problem you are having now is precisely what WINS is designed
>> to
>> avoid, and you can fix the problem easily. You can have everyone register
>> into the same WINS database - you don't have to have multiple ones.
>>
>> Or disable it entirely for all, and don't use network places.
>

sarkiaponius <> wrote:
> On 10 Set, 01:10, "Bill Grant" <not.available@online> wrote:
>> Here is a bit of background. The computer browser service was
>> designed a long time ago when networks were very simple - a few
>> machines plugged into a hub. The browser service and name resolution
>> worked by broadcasting on the wire. Computers communicated using
>> Netbeui.
>>
>> When TCP/IP became common, the browser service was modified to use
>> Netbios over TCP/IP instead of Netbeui. WINS was developed to allow
>> name resolution in a routed network (since broadcasts don't cross
>> routers). WINS also allows browsing across IP routers by allowing
>> the master browsers to communicate directly.
>>
>> Switches do not work the same way as hubs. Browsing does not always
>> work properly on switched networks without WINS (as you have
>> discovered). Machines on the same switch are fine, but machines on
>> different switches end up in different browse lists. WINS solves the
>> problem.
>>
> Okay, we're going to implement WINS as soon as possible,

yes, with 0x8 for the node type.

> though I'm a
> bit worried about this sudden change.

Don't be. And rolling it out is easy if you have DHCP.
>
> One thing more: since we have two domain controllers (I mean Active
> Directory domain controllers), could we make them be WINS server too
> or would it be better not to mix this two roles?
>
> Best regards.

There really isn't much overhead to WINS. Just be sure you stop & disable
the Computer Browser service on all workstations & servers. A GPO is the
easiest way to handle this.