What are the inner workings of a network transfer

workaccount

Just an example lets say I want to transfer files from \\pri-fileserver\data\stuff
to \\pri-fileserver\data\stuffbackup.

Ive just done this with a terminal services session rather than directly from my workstation. What would happen if I did initiate from my workstation, do all the packets have to come onto the network, pass through my NIC and go back to the same server?

degsie

Depends on how your lan is configured. If u are using a hub then ALL nics with see the data but only those pc's with the matching source/destination within the packet/frame will process them. If u are using a switch then the data will be seen only on the nics of the originating and target pc's.

Kali

You didn't really answer his question at all there degsie

What would happen if I did initiate from my workstation, do all the packets have to come onto the network, pass through my NIC and go back to the same server

Yes. Windows isn't smart enough to figure out that the two shares are on the same file-server... so effectively it will copy locally then copy remotely. So for large copies its always best to use a terminal session and complete the file transfers on the server itself.

workaccount

Kali wrote:

You didn't really answer his question at all there degsie



Yes. Windows isn't smart enough to figure out that the two shares are on the same file-server... so effectively it will copy locally then copy remotely. So for large copies its always best to use a terminal session and complete the file transfers on the server itself.

Great. Thats all I needed to know. Cheers.

degsie

Kali wrote:

You didn't really answer his question at all there degsie

Yeah, I see that now. Shoulda have read the question really

azzeretti

Kali wrote:

You didn't really answer his question at all there degsie



Yes. Windows isn't smart enough to figure out that the two shares are on the same file-server... so effectively it will copy locally then copy remotely. So for large copies its always best to use a terminal session and complete the file transfers on the server itself.

You won't believe how this interests me, I really am that sad. I off to sniff it now, but if I had to guess, I would almost certainly say the name resolution would be resolved first and then won't pass any traffic onto the wire, instead shipping it locally.

But we'll soon find out!


EDIT: I read it worng too. Do you mean you are on PC1 and you UNC to \\pri-fileserver\data\stuff and copy back to \\pri-fileserver\data\stuffbackup? If so, then Kali is correct. Not sure what I was thinking of!

Kali

azzeretti wrote:

You won't believe how this interests me, I really am that sad. I off to sniff it now, but if I had to guess, I would almost certainly say the name resolution would be resolved first and then won't pass any traffic onto the wire, instead shipping it locally.

That can't really happen as (afaik) SMB is a client-server model... if you have two file servers and copy a file (using mapped drives/UNC paths) between the two of them it will still copy across the wire from the first server to the client and then upto the second server. Otherwise SMB (or an application-layer extension) would have to make a system call/RPC to the first server to initiate a file-copy/smb session directly to the second.

Now it's possible that Microsoft does actually do that with some implementations of Windows, but from my experience it doesn't and it's always server->client->server.