direct ethernet connection between two wirelessly connected Windows 7 laptops

I've got two systems that are right next to each other, and connected wirelessly to the same router. I want to connect the two of them together with an ethernet cable - both have gig-e and autonegotiation so it should work. I DON'T need the second system to have internet, but I need any specific tweaks to be on that system only.

I do not need to share internet. I need RDP to work, and thats it

The wireless runs on a 192.168.1.x subnet and ICS always runs on a 192.168.0.x subnet so that wouldn't be a problem.

Ideally I want this layout. Can I do this with ICS, or there some other free or open source way?

     +---------------------------+           +-----------------------------+
     | Laptop 1                  |           | Laptop 2                    |
     | Client- mobile            |           | 'server'- stationary system |
     |                           <-----+----->                             |
     | RDP client                |           | RDP Server                  |
     | MUST have wireless access |  ethernet | Runs ICS or similar         |
     +---------+-----------------+           | wireless access optional    |
               |                             +-----------------------------+
               |
               |
               |
               |
               |
               |
               |
               +---------------+     wireless to internet

Journeyman Geek

Posted 2011-06-21T02:07:05.587

Reputation: 119 122

2I like the diagram. – KCotreau – 2011-06-21T02:16:37.617

@Journeyman Geek Thanks for the info. Of course, I realized that switches started using the uplink (sometimes on all ports) a long time ago. I did not realize that NICs also had that now. I think I mis-read what you were trying to do, so I will delete my answer and re-think it. – KCotreau – 2011-06-21T02:45:43.123

i worked most of it out, eventually. It was oddly simple ;p – Journeyman Geek – 2011-06-21T02:51:58.183

@Journeyman Geek "It was oddly simple", that was the reason I thought maybe it was a crossover cable. That could really trip someone up. – KCotreau – 2011-06-21T02:55:58.143

what tripped me up was forgetting about static IP addresses. I've been using ICS or routers for the most part so i never really had to think about this for the most part. – Journeyman Geek – 2011-06-21T03:00:16.057

@KCotreau: Auto-negotiation is part of the Gigabit spec standard. – paradroid – 2011-06-21T04:08:33.320

@paradroid Thanks, I learned that tonight. I have enjoyed answering questions in my first three weeks here, but I have also learned a thing or two. – KCotreau – 2011-06-21T04:19:17.293

Answers

Apparently, assuming one of your systems supports autonegotiation the following process will work

connect both the systems with an ethernet cable - a plain vanilla one will work with autonegotiation, else you'll need a crossover. Most modern systems support it.
You'll need to set up both systems with static IP addresses, ideally from one of the 3 private blocks. Since most home networking uses the class C block, i chose to use the class A block, using the subnet mask 255.0.0 from here.

Currently i don't know what is the proper default gateway to use for the 'server', so as far as the systems are concerned, its a private network - so any sharing will need the ports explicitly opened in the firewall. I need to work out how to fix this.

In order to set up static IP addresses

go to Control Panel\Network and Internet\Network and Sharing Center

select change adaptor settings

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select the Local Area Connection/ethernet connection (it seems to vary between windows 7 and 8)

select properties

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Select Internet Protocol Version 4 and hit properties

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I use these settings for the 'server'

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for the 'client'

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You can set the connection type as anything on the 'client' - it will be stuck as 'public' on the server.

you can test this with ping

Journeyman Geek

Posted 2011-06-21T02:07:05.587

Reputation: 119 122

Yep, you don't need gateway, tested myself. BTW, does this work on all new Windowses (8+) on 1000TX Ethernet or on 100TX too? – Suncatcher – 2020-02-05T07:23:39.673

I've not run this set up recently - I had a peculiar requirement at the time and much worse networking than I do now. I don't think networking has fundamentally changed much and you ought to be running at fairly close to line speed. – Journeyman Geek – 2020-02-05T07:39:31.060

2You don't need a gateway. That is only to route traffic on those NICs to a different network. You are not doing that since you use a totally separate NIC with a gateway to get to the Internet. For RDP, open 3389. – KCotreau – 2011-06-21T02:50:23.390

windows 7 assumes any network without a gateway is insecure, amusingly. I cannot change the connectiont type on the 'server' system to anything else. – Journeyman Geek – 2011-06-21T02:52:56.013

I have these settings on the two computers connected with a single RJ45 cable, and it worked:

PC-1 (windows 8)：
    IP: 192.168.200.1
    Mask: 255.255.255.0
    Gateway: 192.168.200.1
    DNS Server: <leave blank>

PC-2 (windows 7)：
    IP: 192.168.200.2
    Mask: 255.255.255.0
    Gateway: 192.168.200.1
    DNS Server: <leave blank>

I had to set the gateway, otherwise it's not working.

deerchao

Posted 2011-06-21T02:07:05.587

Reputation: 101