Network two computers

[rancid-lemon]

Hopefully a question with a simple solution:

I have two computers and a normal ethernet cable, can i plug em in to each other and copy files across machines?

I say normal ethernet cable, meaning not crossover, which part of my brain tells me I need and another part tells me that the crossover can be handled by the NICS.

Cheers,

rancid

[Nick H. Supervisor]

You'll need a crossover cable. It's not possible with a normal ethernet cable.

[Olemus]

It all depends on the NICs being used, some will know what your trying to do and switch them and some won't.

[sc302 Veteran]

If one of the 2 nics are gigabit nics then a normal cable will work. A gigabit nic will autosense the necessity to cross over and do so if needed, it is built into the gigabit standard protocol. So only one gigabit nic is needed because only one side needs to cross to establish communication.

A cross over cable is where one side is normal and the other is reversed, in hardware one side is normal (say 10/100) and the other side is cross (gig)..only 1 side needs to be gig for this to function.

[Nick H. Supervisor]

  On 29/06/2011 at 19:58, sc302 said:

If one of the 2 nics are gigabit nics then a normal cable will work. A gigabit nic will autosense the necessity to cross over and do so if needed, it is built into the gigabit standard protocol. So only one gigabit nic is needed because only one side needs to cross.

Huh, I didn't know that. Thanks for the info!

[richardsim7]

Dammit sc302 ya beat me to it! :p

[sc302 Veteran]

:)

[Roger H. Veteran]

Yeah that sc302 :shakesfist: hehe

Even if neither are as long as they support MDI-X it will work as well but finding out is the problem. So yeah, 1Gbit cards make it easy.

[+BudMan MVC]

  On 29/06/2011 at 19:59, Intrinsica said:

Huh, I didn't know that. Thanks for the info!

Guess you don't read your IEEE standards very often then? ;)

Is it just me that reads these things?? Kind of given if your going to work in the field to keep up with the actual standards, so whats next? your going to tell me you don't read the RFCs either? :rofl:

Here is the actual clause in the IEEE 802.3 2008 standard.

Now in the standard it is actually only listed as optional, but I have yet to see a gig nic that does not support it.

[rancid-lemon]

Superb! Thanks for the replies :)

Both NIC's are gig so we are good to go. Am currently away from my pc but should be able to give it a go when I get back, hopefully tomorrow.

If both are running windows is there any network set up required or can I just \\computername in explorer?

Thank you again guys, you have just saved me a lot of hassle!

rancid

[sc302 Veteran]

Each comp needs its own ip address then you should be able to use \\computername or \\ipaddress.

[+BudMan MVC]

by default it will use APIPA for an address, ie something rand that starts with 169.254 so yeah once you turn on file sharing, and if you don't have any firewalls blocking sure \\computer name and you should see whatever shares you setup.

[rancid-lemon]

Win, ty chaps. Will give this a bash later.

rancid

[rancid-lemon]

Job done. Worked like a charm after enabling file sharing on both computers.

One question I do have after doing this is as follows:

To turn on file sharing I had to change the network type to private. Windows prompted me to treat all future networks as private or just this one, obviously (I hope) I chose the 'just this one' option. My question is, how does windows know which network it actually 'is'?

Currently it is just called 'Unidentified network', does this mean that any other network that gets called Unidentified network will get set as private from now on?

rancid

[sc302 Veteran]

By ip range, when you connect to a different ip range it will change. I think it is also smart enough to notice a router change by mac address, not 100% on that though. At the very least ip change determines a significant network change where it will prompt you also.

[+BudMan MVC]

"I think it is also smart enough to notice a router change by mac address"

That would be simple enough test by just turning off you machine, change the mac of your gateway device and see if still thinks same network.

I have been looking for a few minutes, and can not seem to find exactly what are used as the identifiable characteristics of a specific network. Domain is easy, if it can not contact domain controller then its highly unlikely your on a domain ;)

But how does it determine private from public? Or unidentifiable - from some of the info I came across if there is no default gateway then it would be an unidentifiable network and would then prompt you for what it is. There is info how to fix this issue by removing bad default gateways that might point to a specific interface on your box, etc.

But I would love to find the whitepaper or technet blog or something that goes into the details of this process of how windows determines and names, etc. If anyone has a link to that would be great, if I find it before I get bored with looking or sidetracked I will post it for sure.

edit: here you go, still reading it - but this looks like the info looking for about what is actually used to identify a specific network, etc.

http://blogs.technet.com/b/networking/archive/2010/09/08/network-location-awareness-nla-and-how-it-relates-to-windows-firewall-profiles.aspx

Network Location Awareness (NLA) and how it relates to Windows Firewall Profiles

still reading the details, but this jumped out at me - which I thought was the main reason for unidentified and this confirms it. And would make sense for sure in the OP setup of just directly connected machines.

"It simply means that Windows cannot uniquely identify the network and will apply the public profile. Generally this is because there is not default gateway and it is not a domain joined machine."

edit2: and sc302 this article does mention the mac address of the gateway you mentioned

"Default Gateway MAC address - The MAC address is more unique than an IP address and therefore makes a better characteristic"

But is just one of the many characteristics used, each network is given a unique GUID based upon the characteristics of that network. Really good read - enjoying it!

[rancid-lemon]

Wow, a question that budman couldn't answer off the top of his head! Must be getting a bit rusty :whistle:

That table was quite useful. Looks like I don't have to worry about the Unidentified network issue then. Seems to take a whole host of characteristics in to assign a GUID.

Thanks to both of you for the replies.

rancid