Tcp/ip & broadcast 1

[rgao]

Hi, there
I'm new in this field, i hava some questions about tcp/ip,I hope someone can help me find answer

Q1: does tcp/ip support broadcast? browering "my network place" reply on broadcast?
Q2: i have two pc connected by crossover cable,they can ping each other but can not access shared files(everyone has permission to access these files)?

Thanks in advance

rgao

 

[jimbopalmer]

Both 'network neighborhood' and 'file sharing' on PCs frequently use Microsoft protocols, not TCP/IP. (some can use Microsoft Protocols over IP, so at a low level they routable)

A1: So yes, TCP/IP supports broadcasts in a subnet, between subnets you need a router. I am told you will need a 'Master Browser' in each subnet, for network neighborhood to work between subnets.

A2: Ping is a TCP/IP protocol, so that is working. File sharing is Microsoft Networking, which may not be set up right. (FTP would be the TCP/IP file transfer ptotocol, but I don't think you are using it)

I tried to remain child-like, all I acheived was childish.

 

[John Lewis]

Only way to keep fresh on this is to go over it now and again, so here goes . . .

A few common misconceptions to address. Don't mean to pick by any means, but could save some headache later . . .

Microsoft file sharing and Network Neighborhood relies upon SMB. SMB can't do anything by itself, it must have a lower level protocol to do the real work. Currently, SMB usually runs over NetBIOS, which also can do little on its own, but agian must rely on yet a lower level protocol. This is where TCP/IP comes into the picture. Point is, SMB is used over top of TCP/IP, not instead of TCP/IP.

On a side note, TCP/IP is not really required. SMB can ride over top of other protcols that don't require NetBIOS and NetBIOS can ride over top of protocols other than TCP/IP. That makes the statement ". . .frequently use Microsoft protocols, not TCP/IP" somewhat correct in one context, but the information provided would indicate that SMB is layered over NetBIOS and TCP/IP in this case.

Next to the broadcasts. NetBIOS relies on broadcasts for name resolution. It is entirely possible to share files without broadcasts, but it is not possible to 'browse the network' without otherwise providing for NetBIOS name resolution. If different subnets are involved, a router will not help with the broadcast issue. Routers forward data between subnets, but only data that is addressed to a specific address. Broadcasts can cross subnets only by using a bridge. Subject for another day.

Ping is not a protocol, but an application that uses the ICMP protocol, which is part of the TCP/IP protocol suite. The fact that ping works does tend to indiate that TCP/IP is connecting properly, however it does not really indicate that broadcast messages are being handled properly.

All of that, and still haven't really touched on the problem. So here goes . . .

A few basic things must be in place in order for file sharing to work. Start by sharing a resource on both computers. Even if you don't really want resources on one of the computers to be shared, go ahead and share a drive until you get things working -- helps things along sometimes. Also makes sure that the proper services are configured on both computers.

Make sure that the workgroup names are the same on both computers. Must be a workgoup name at this level, not a domain.

Next, check out your name resolution. Just for illustrative purposes, I'll call your computers COMP_A and COMP_B. Complete all of the steps as directed even if you get an error at some point. Also, note what the specific error is. Ping can return many different error messages and they all mean different things. I know you said that ping worked, but you didn't say how you were using it, so bear with me here.

1) Open a command window on COMP_A and type 'PING COMP_A' -- remember to replace COMP_A with the name that you assigned to COMP_A.

2) From COMP_A try 'PING COMP_B', again replacing the name with the name you assigned.

3) In a command window on COMP_A, type 'NET VIEW \\xxx.xxx.xxx.xxx', replacing the xxx.xxx.xxx.xxx with the IP address you assigned to each COMP_A. Repeat with the IP of COMP_B. Should give a list of the shared resources on the computer.

4) If step 3 looks good, in a command window on COMP_A, type 'NET VIEW \\COMP_B', replacing the COMP_B with the name you assigned.

5) If you all is well so far, skip to step 6. If you received an error on step 3, skip to step 7. Otherwise, in a command window on COMP_A type 'NET USE M: \\xxx.xxx.xxx.xxx\SharedDrive', replacing the xxx.xxx.xxx.xxx with the IP address you assigned to COMP_B and SharedDrive with the share name that you assigned to a shared resource on COMP_B. If all is well, M: on COMP_A will point to the shared drive on COMP_B.

6) If you are good through step 4, but you still don't see anything in the browse list, in a command window on COMP_A type 'NET USE M: \\COMP_B\SharedDrive', replacing the COMP_B with the name you assigned to COMP_B and SharedDrive with the share name that you assigned to a shared resource on COMP_B. Again, if all is well, M: on COMP_A will point to the shared drive on COMP_B.

7) If 3 and 5 look good, but the others give problems, it would indicate a name resolution problem. Either way, if you are still having any problems, at a command prompt, type 'nbtstat -c' (it is case sensitive). Should list both of your computers 3 times.

Kinda long, but should get you on the way to getting this fixed. If you need further assistance, report back with any error messages you enounter in any of the steps, the full output of step 7, and the version of Windows running on each computer.

 

[GeoffTCS]

mhkwood

Good post! Concise and informative

Geoff

 

[rgao]

Thanks for all reply
Mhkwood, your tips are helpful,follow your instruction i already fix the problem, it's name resolution problem,Thnaks again.

rgao