Accessing two networks on the LAN port over WIFI

Kaptainkugelkopf · 2020-08-31T13:33:02.445Z

I have a problem with my GL-AR300M configuation.
I want to access two connected switches with different subnets over WIFI.
They are bridged and connectet to the LAN port.
(See Image for the setup)

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Router

Image Router hosted in Freeimage.host

At the moment its working if i change the IP of my WIFI adapter on my PC to the corresponding Network. (For example 172.21.13.100 to connect to the VNC)
But like this i cant connect simultaneously and have to change my IP all the time.

Is there a way to route the traffic so i can leave DHCP on my PC on and still connect to both switches and the Internet?

I tried to set up some local static routes from the LAN port.
I can now Ping all the Devices but can’t connect via VNC…etc.

Is this a possible setup?
Any ideas on how to configure this?

Kaptainkugelkopf · 2020-09-01T07:40:42.882Z

Here is the TCPdump when i try to connect to the VNC Server.

01:03:19.260239 IP PG004.lan.56417 > 172.21.13.153.5900: Flags [S], seq 961657843, win 8192, options [mss 1460,nop,wscale 8,nop,nop,sackOK], length 0
01:03:19.260239 IP PG004.lan.56417 > 172.21.13.153.5900: Flags [S], seq 961657843, win 8192, options [mss 1460,nop,wscale 8,nop,nop,sackOK], length 0
01:03:19.260530 IP 172.21.13.153.5900 > PG004.lan.56417: Flags [R.], seq 0, ack 961657844, win 0, length 0
01:03:19.260560 IP 172.21.13.153.5900 > PG004.lan.56417: Flags [R.], seq 0, ack 1, win 0, length 0
01:03:19.763959 IP PG004.lan.56417 > 172.21.13.153.5900: Flags [S], seq 961657843, win 8192, options [mss 1460,nop,wscale 8,nop,nop,sackOK], length 0
01:03:19.763959 IP PG004.lan.56417 > 172.21.13.153.5900: Flags [S], seq 961657843, win 8192, options [mss 1460,nop,wscale 8,nop,nop,sackOK], length 0
01:03:19.764249 IP 172.21.13.153.5900 > PG004.lan.56417: Flags [R.], seq 0, ack 1, win 0, length 0
01:03:19.764278 IP 172.21.13.153.5900 > PG004.lan.56417: Flags [R.], seq 0, ack 1, win 0, length 0
01:03:20.267022 IP PG004.lan.56417 > 172.21.13.153.5900: Flags [S], seq 961657843, win 8192, options [mss 1460,nop,nop,sackOK], length 0
01:03:20.267022 IP PG004.lan.56417 > 172.21.13.153.5900: Flags [S], seq 961657843, win 8192, options [mss 1460,nop,nop,sackOK], length 0
01:03:20.267283 IP 172.21.13.153.5900 > PG004.lan.56417: Flags [R.], seq 0, ack 1, win 0, length 0
01:03:20.267311 IP 172.21.13.153.5900 > PG004.lan.56417: Flags [R.], seq 0, ack 1, win 0, length 0

smiths · 2020-09-01T14:43:33.710Z

It complicated and can be done (Well at least I could do it on an MT300N-V2, so I am guessing it can be done on AR300).

I would avoid the router config altogether.

Why not on windows:
Set a static IP address on the Wifi interface uner IP4 settings as you do at the moment?
Then go to advanced and add the ip address and mask for the 2nd network?

It would avoid swapping IP addresses on PC wifi all the time. Is 30 seconds to setup.

Simon

Kaptainkugelkopf · 2020-09-01T14:47:04.889Z

Yea, probably gonna do it like this.
I have to change the IP to DHCP again to get on the internet.
its not nice but seems like this wont be solved very easy

smiths · 2020-09-01T15:04:17.195Z

Ok, a little more about the 2 networks.
Do they have DHCP servers, how do they get to the Internet?

Simon

Kaptainkugelkopf · 2020-09-01T15:05:49.514Z

These are just simple switches. With PC’s or industrial eq on it.
I want to connect via wifi to the internet.
use the router as access point.

smiths · 2020-09-01T15:35:34.366Z

The wifi and the LAN port are bridged. This means packets from one can flow to and from the other. This does not mean they will mind you. Above bridging is IP address and subnetting. To traverse the bridge you have to be on the same IP network.

When the destination is the same subnet, your computer asks everyone "hey who has IP address 172.21.13.153, and the device sees this and says I am at mac address … Because you have a bridge, and change your IP address, this is why traffic flows over the bridge to the device on the switch.

When the destination is a different subnet your computer says that is not local, I’ll send that to my default gateway. So when you are set to DHCP, your computer forwards traffic for 172.21.13.153 to you wireless internet connection. Not gonna find it there.

To let the AR300 sort things out, I am guessing we will need to define 2 additional networks , not sure from your wireshark above of the topology.

Can you get to Luci (on a MT300N-V2 its Other Settings->Advanced)? If so we might be able to sort it out. I think you will need to plug one of the switches into the wan port though, and we can repurpose its use, I hope without upsetting the GL.inet interface.

Your use case seems somewhat removed for what the AR300M was designed for!

This means what you are trying to do is fairly complicated.

I have not got an AR300M, so I do not know how they are configured and use openwrt, but what you want to do is quite possible in openwrt.

Simon