Connect 2 Devices via Ethernet on Secondary Network

blksith0

Senior Member
OS's: Windows 10 Enterprise

I'd like to connect two different devices together via ethernet so that LAN apps behave better.


However both devices (running windows 10) are connected to the same wireless network, and I don't know how to configure a direct-lan-ethernet connection, let alone how to make this 2nd network not conflict with the 1st.
What do?
 

Neemobeer

Windows Forum Team
Staff member
Should be pretty straight forward. You will want to get a cross-over Ethernet cable, although I think Windows 10 may be smart enough to reverse the logic on the network cards, but the cable would be the best idea.

Pick some arbitrary non-routable subnet A,B or C 10.x.x.x, 172.18.x.x-172.32.x.x or 192.168.X.X that isn't the same as the wireless network LAN.

I'll just use 192.168.55.0 as the network with a 24 bit mask 255.255.255.0

Assign computer A with a static address on the Ethernet connection 192.168.55.1, Subnet 255.255.255.0 gateway, and DNS are not required.
Assign computer B with a static address on the Ethernet connection 192.168.55.2, Subnet 255.255.255.0 gateway, and DNS are not required.


Then it's just a matter of configuring your network based application on the client side to point to the server address (192.168.55.0 network) and the server side set to listen on the network card with the 192.168.55.0 address.
 

BIGBEARJEDI

Fantastic Member
Premium Supporter
Well, Neem's suggestion will work, but on a home router it's certainly not going to be optimal.:scratch: I think you'd be better server by buying a 2nd wireless router, and hook PC-#A to your old router, and PC-#B to your new router; both Wi-Fi connected. Otherwise, you'll have contention and beaconing on your Ethernet connection between the 2 PC's, even if on separate subnets!:alien: You're PC on each subnet/wireless connection to your router will be fighting sending/receiving Ethernet packets between the NIC and the WLAN (internal or external Wi-Fi card/adapter). This is NO-BUENO! :noway:

This method will also effectively cut your Internet speed or bandwidth in half, since 50% of the wireless signal must be divided between 2 subnets, each with 1 PC on it. It will work, but I believe it's not going to give you the performance boost you are looking for. To do it right, you should get a Cisco 2600 or 3500 industrial router which has subnet fast-Ethernet switching and can handle a direct-link between PCs on different subnets through a mechanism known as LOAD-BALANCING. Home routers do NOT have this feature (MIMO is sort of poor-man's Load Balancing). Cost of these routers is from about $2,500-$6,000 US. This is pretty pricey to really fix your problem. You could also pick up these routers used on ebay for a fraction of the price; say about $500-$800 US or so.;)

Using those devices requires advanced networking skills; and if you decide to do that, you should consider hiring a Cisco-Certified CCNA or CCIE Engineer conversant in Cisco IOS (the Cisco OS)to design and install it for you. Pricewise, you are looking at several hundred dollars to several thousand for one of these experts to put in this equipment in your home. :cash::cash:[Labor Cost alone]. I have done so for several Clients over the years.

Just food for thought.:andwhat:
<<<<<BIGBEARJEDI>>>>>
 

blksith0

Senior Member
It seems odd that such a simple task would need to be done in such a complicated manner Bear.:andwhat:

What would be cool is a software approach that isolates certain programs to only recognize certain network adapters. That way I could just make Synergy forced to use the ethernet crossover while everything else uses the wifi dongle as usual.

I'll update how it goes when my crossover cable arrives.
 

BIGBEARJEDI

Fantastic Member
Premium Supporter
Yup, blksith0, I agree. Maybe one of our network experts (we have several) will chime in with something new I'm not aware of. I've been out of Corporate IT for several years now, as I am retired and just do basic computer repair, and occasional home networking. But, I did spend 35+ years doing IT stuff as you can see, so at present, I can guarantee this solution will work with Cisco routers. And THEIR software will definitely do this, as I had projects where we had to implement your configuration. No Home router equipment I've seen for under $500 US will do what you are talking about; at the current moment.

Looking forward to your test result.

Best of luck,:teeth:
<<<BBJ>>>
 

Neemobeer

Windows Forum Team
Staff member
It seems odd that such a simple task would need to be done in such a complicated manner Bear.:andwhat:

What would be cool is a software approach that isolates certain programs to only recognize certain network adapters. That way I could just make Synergy forced to use the ethernet crossover while everything else uses the wifi dongle as usual.

I'll update how it goes when my crossover cable arrives.
There is something that will do that, it's called the routing table. Once you're configured from my above post you can ping the "server" say ping 192.168.55.1 that should send an arp request and add a route associated with the correct interface. Most specific route wins and traffic will go out the correct interface.
 

blksith0

Senior Member
Okay,
using a crossover I can connect the two and after simply manually configuring their IPv4 settings
Setup 2 pc network with cross over cable
(basically each computer's default gateway points to the other's)

Now my problem is that one of my computer's (A) windows firewall is blocking the other one (B) completely; I can't even ping it.
When I disable A's firewall, B can ping A.
And after testing, the same is true vice-versa.

So now what do I need to do to allow traffic through these two computers without disabling their firewalls completely? AFAIK windows firewall allows ports/programs but I dont know about specifying a certain network connection/adapter.


 
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BIGBEARJEDI

Fantastic Member
Premium Supporter
Are either of these computers laptops?? If so, that could be your problem! Many laptops cannot running Wi-Fi and Wired Ethernet (both Embedded Adapter Chips) simultaneously!! This is true on many makes and models, and has been so for several years. :eek:

Also, your Wi-Fi network should not be configured as a Public Network, as that changes built-in Firewall Settings in Windows as well as 3rd party AV programs such as Norton, Avast, McAfee, and TrendMicro.:noway: I'm not sure why you chose making these 2 networks different, but that's certainly a step in the wrong direction.

If both of these machines are laptops, you will have to DISABLE the Wi-Fi network on BOTH laptops to use a Direct Connection such as you are attempting. In addition, you will need to make sure that neither laptop is set to Public Network, but rather both are set to Private Networks. Direct Ethernet connections are generally not allowed on Wi-Fi. Further, you will need to make sure that BOTH laptops or BOTH machines are using W10 Homegroups as well. Homegroups is capable of directing network traffic through both Wi-Fi and Wired networks (LANs), but it sorts out some of the mumbo-jumbo ip addressing you have to go through to make it work if you don't use Homegroups. You will have to pick 1 of your 2 laptops or machines to be the Master, and then connect the 2nd or Secondary laptop or machine to the Homegroup via the Password generated by the W10 Homegroups app.

Don't know if this will work; but I can tell you that no one else on any of the 5 forums I volunteer on has this working in W10; so it's certainly not as trivial as you make it out to be.

Let us know if you get it solved and post back here to share your final solution with our forum users.

Best,:encouragement:
<<<<BBJ>>>>
 

blksith0

Senior Member
I prefer to have my wi-fi as a public network so that it's harder for any other random devices to see my computer, I'd rather explicitly allow devices.

My laptop also seems to be able to handle the simultaneous connection, maybe because they're on separate subnets (192.168.2 instead of 1). When I turn both firewalls off, the pc's are pinging each other while both have internet access.
- Although to be fair, the laptop did not have internet access initially, but after removing the Ethernet connections DNS settings, it works now.

So now I've followed this guide to disable the firewall on my ethernet connection (warning: usually a bad idea)

I believe I'm close now, but the application I'm trying to connect is giving a Connection Refused error, but that's only after the firewall's are off. I know it's a problem somewhere buried in A's windows configuration because booting into a fresh install of win10 accepts the connection just fine.

Edit: okay, 7 am, no sleep, but I got it working. Synergy works over LAN now, yay. The reason synergy worked on the fresh install is because I simply had a non-default port configured on A. Matched up the ports and now its good. I figured everything was connected properly since they could initially ping each other, so hooray.
 
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Neemobeer

Windows Forum Team
Staff member
Yeah a connection refused generally means the device is not listening on a given port. You can download nmap (Zenmap gui front end) and scan the remote system you should see <port #> open when it is listening.
 
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