NETBIOS BLOCKING ON ETHERNET NETWORK

[baboo]

We have set up a 10M Lan with Compaq P.C's running Win 95 connected with a Cisco 1538M hub to a Cisco 1600 router. The problem is that none of the machines can see each other on the Network Neighbourhood. Am I correct in assuming that the broadcasts are being blocked by one of the devices? If so, how do I rectify this?

 

[lardum]

NetBIOS isn't routable. So if you mean that you can't see computers on the other side of the router, that's why.

Try setting up a WINS-server. Think that will work.

Regards

Lars

 

[tgaudet]

If this is a Windows network then you must install NetBUI and TCP/IP if it is not already installed. This will allow NetBios to be routed (actually, it sort of piggy backs on top of TCP/IP)

 

[Kerzon]

Actually, that's not entirely correct. NetBeui is not a routable protocol as lars stated above, Neither is NetBios because Microsoft, in their infinate wisdom decided to keep NetBios at layer 5 instead of layer 4. (OSI model) You are correctin the fact that NetBios piggy-backs TCP/IP, but in order for a machine to connect in that kind of enviroment (Non WINS) it needs File and Printer sharing installed.

If you were to go into the network control panel, make sure that all machines have File and Printer sharing for Microsoft Networks installed. This will allow one machine on the network to become the Browse Master (Kinda like a WINS server, but not as advanced). The rest of the machines will announce to the Master, and boom, you can see all of your machines.

Hope this helps!

 

[axslinger]

In all fairness to MS, NetBEI/NetBIOS is not an MS product. It originally came from IBM and has never been routable. And I have been fighting with the same problem for a couple days now. I have LMHOSTS files on both ends. No NT boxes on the network. I have enabled the Win9x boxes File and Print Sharing and turned on the Browse Master option. I still can't see the machine on the other end. But I can ping it fine, as well as the serial and ethernet port of the remote router. Even worked with Cisco for over an hour and still nothing. Do you think Bridge mode might be a solution since everything would effectively be on the same network?

Brian

 

[Kerzon]

Bridging would really only be used if you have more that one router on the network. I can't see why that would be a problem.

Try this first (if you haven't done it already):

Goto a command prompt, type net diag. Answer no to the question:

Is Microsoft Network Diagnostics currently running on any
other computers on the network ? (Y/N)

This will put the first machine into Diagnostic Server mode. On the second machine do the same. If they can talk to each other, I would recommend downloading Microsoft DUN 1.3. Yes, I know it is a Dial-Up upgrade, but it also upgrades the TCP/IP stack as well as the NetBios DLLs. Here's the address:

http://www.microsoft.com/windows95/...mended/S_WUNetworking/dunwinsky2k/Default.asp

Otherwise, try only enabling one Master Browser, as there should be only one on the network. Also, if you are using NetBeui, make it the default protocol. (You can do that in the Network Configuration screen.)

It would be easier if you had a WINS server on your network, because then you would be able to run only 1 network protocol, TCP/IP.

But alas, I'll keep looking around if none of the above work.

G/L! B-)

Andy

 

[axslinger]

Andy,

Thanks for the info. I will print it out and take to the job site the next time I go there. I talked with Cisco yesterday. Don't ask me why I didn't catch this before but late yesterday the Cisco tech had me do a Show Interface Serial1 and there were literally thousands of input errors and about half as many CRC errors, in a period of about 4 hours. I checked the other end and it was the same way. At this point we believe its an issue with the T1 line. I will call Ameritech today and have them check the line out. But I WILL keep you posted.

Brian

 

[Kerzon]

Brian,

Mike is correct, also try the following:

Turn on udp forwarding of ports 137 and 138 on the routers. This is how you do it:

ip forward-protocol udp 137
ip forward-protocol udp 138

Then, on the interface enable an ip helper address:

ip helper (other ethernet subnetwork address)

In a sense:

router# conf t
config> ip forward-protocol udp 137
config> ip forward-protocol udp 138
config> int s1
config-if> ip helper 10.10.2.1

Hope this helps...

Andy [sig][/sig]

 

[XoverIP]

FYI-

Technically speaking, NetBIOS IS routable. However, if trying to route NetBIOS, it must be encapsulated under another transport protocol.

sko0bz [sig][/sig]

 

[Kerzon]

Actually, NetBios will never be routeable, since it is a layer 5 protocol. TCP/IP resides at layer 3. It's a small 2 layer encapsulation that takes place. (NetBeui is a layer 4 protocol)

andy [sig][/sig]