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I have a network an a subnetwork on 2 ends of a powerline Ethernet adapter. I would like to allow access to the machines on the subnetwork to machines on the network without sending all the traffic from the subnetwork over the powerline adapter.

my setup is as follows: Both routers are ASUS RT-AC66Us [1][2]

  Modem
    |
----+-------------------------------------------
| router-a / lan-a / LAN                       |
| Wide area IP: 1.2.3.4 (external/Internet)    |  
| local IP (192.168.1.1 / Mask: 255.255.255.0) |
|                                              |
| static route:                                |
|    {Network IP:192.168.2.0                   | 
|           Mask:255.255.255.0                 |
|        Gateway:192.168.1.120                 |  
|      Interface:LAN}                          |
----+-------------------------------------------
    |
Powerline
    |
----+---------------------------------------------
| router-b / lan-b / SubLAN                      |
| LAN IP: 192.168.1.120 (should be labelled WAN) | 
| local IP: 192.168.2.1 / Mask: 255.255.255.0    |
|                                                |
| static route:                                  |
|    {Network IP:192.168.1.0                     |
|           Mask:255.255.255.0                   |          
|        Gateway:192.168.1.1                     |
|      Interface:WAN}                            |
|            NAT:off                             |
----+---------------------------------------------
    |
---------------------------------------
| Computer/Server IP: 192.168.2.166   |
---------------------------------------

The subnet is working as a subnet, I can access network resources attached to the LAN from the subLAN, but I can't get the subLAN to forward any traffic coming from the LAN, so I can't access the server from the LAN.

F.W.I.W. I have a media server running on the same machine as gaming pc, and I have the subnet set up for game streaming, but the tv is on the LAN, and can't access the content unless I merge the networks. I am not married to the subnet situation, but I need a way to prevent my gamestream from traveling over the powerline adapter twice.

David
  • 2,362
Aaron Ladd
  • 449

1 Answers1

1

Let's call your lan lan-a and your sublan lab-b.

Firstly, you don't need two subnets, you just need a switch on lan-b, then have all your other devices on lan-b plugged into the switch. Ethernet switches do not echo all traffic across a segment like an Ethernet hub (but hubs are not very common these days). [1]

I suppose there could be other broadcast traffic and protocols from hosts on either side of your powerline adapters that you are trying limit. Usually this traffic relating to devices trying to discover things about your network, like DLNA, UPnP, mDNS/zeroconf/bonjour and other networking protocols.

So if you are looking to limit the broadcast traffic it could be two things:

1.) While you may have disabled NAT, you may still have your firewall on router-b turned on, and this is what is blocking traffic from lan-a. Is your firewall on router-b switched on?

2.) It could be that you do not have the routing configuration setup correctly on your router-a. Is your static route set to lan?

3.) Even if you have everything setup correctly with these routers, it may just not be possible given how the web base user interface limits what you can do with them. Try setting up an old computer running linux to act as the bridge/router between your 2 subnets.

4.) Even with your two subnet setup, some broadcast/sniffing/discovery traffic will still pass through your powerline bridge, such as MS SMB discovery traffic, other traffic will not go beyond your IP subnet as limited by your netmask.

 Modem
     |
----+-------------------------------------------
| router-a / lan-a / LAN                       |
| Wide area IP: 1.2.3.4 (external/Internet)    |  
| local IP (192.168.1.1 / Mask: 255.255.255.0) |
|                                              |
| static route:                                |
|    {Network IP:192.168.2.0                   | 
|           Mask:255.255.255.0                 |
|        Gateway:192.168.1.120                 |  
|      Interface:LAN}                          |
-------+----------------------------------------
       |
================
Powerline Bridge
================
       |
-------+------------------------------------------
|  WAN PORT                                      |
| ********************************************** |
| router-b / lan-b / SubLAN                      |
| LAN IP: 192.168.1.120 (should be labelled WAN) | 
| local IP: 192.168.2.1 / Mask: 255.255.255.0    |
|                                                |
| static route:                                  |
|    {Network IP:192.168.1.0                     |
|           Mask:255.255.255.0                   |          
|        Gateway:192.168.1.1                     |
|      Interface:WAN}                            |
|            NAT:off                             |
| ********************************************** |
|              LAN PORTS                         |
--------+-----------------------------+-----------
        |                             |
--------+-------------      ----------+-----------
| lan-b Switch       |      | Computer/Server    |
|                    |      | IP: 192.168.2.166  |
----+-----------------      ----------------------
    |
    |
   /|\
--+++++--------------- 
| other lan-b hosts  |
| 192.168.2.x/24     |
----------------------
David
  • 2,362