MT300N-V2 network capture wan-lan

Technical Support for Routers
1

Hi,

I am trying to use GL as a network analyzer while developing custom network device on the microcontroller. Hubs and switches normally discard invalid packets so I cant use Wireshark on the pc. I was able to use GL for this with tcpdump before upgrading the firmware version, but I don’t remember what exactly I had to change to make it working. Network configuration is not my forte.

My micro is connected to the LAN port and my office switch where PC is connected is on the WAN port of the GL.
I am using OpenWrt 18.06.1

I am able to ping anything on the network apart from LAN device.

2

Is Microcontroller on LAN side and PC is on WAN side? If so and GL-MT300NV2 is in Router mode, then the PC cannot reach the Microcrontoller. You can try port forwarding, disabling the firewall or using Extender mode.

3

Yes, PC is on the WAN side.
Actually I just disabled the VLAN Switch and PC was able to ping the microcontroller, but then I was not able to ping or connect to GL anymore. So I reverted the change. Disabling the firewall didnt help. I think its is somehow filtering the traffic between the VLAN’s.

4

I don’t know really if it will work but WAN is in WAN firewall zone.
Try to put it in LAN zone.
Or put PC in LAN port not WAN.

5

My understanding is that Openwrt does not normally allow management from the WAN side. You would have to do port forwarding through the firewall.

Why do you need VLAN’s.

6

No, I dont need VLAN’s, I just noticed when I disabled them that I actually got access to the microcontroller. Also, I dont really care which port is connected to what. I can use WAN for PC or microcontroller…
I wasnt aware that I wont be able to administer GL from WAN port, might have been on the right track with disabled VLAN’s but thought I messed up something else when I was not able to ping GL anymore.

7

Regardless of which port I use for PC as soon as I disable VLAN (it is enabled by default), GL is not accessible any more but microcontroller can be pinged from PC. I might need to enable Wifi and use that for connecting to GL…

8

That is strange. I just tested on my router (GL-MV1000W) to port forward traffic on WAN Port 80 to LAN Port xxx.xxx.xxx.xxx Port 80, where xxx.xxx.xxx.xxx is the router’s LAN IP address. I am immediately able to access router management via http://yyy.yyy.yyy.yyy where yyy,.yyy.yyy,.yyy is the router’s WAN IP address. Since the router does NAT, you have to know access via its WAN IP.

EDIT: I did the port forwarding for SSH on Port 22 and it works also.

9

update: I was able to get access to microcontroller from PC passthrough the GL, by setting VLAN port 1 WAN to untagged and port 2 WAN to off. Firewall is disabled,LAN is set as a bridge (eth0.1;eth0.2), WAN is set as a (network device eth0.2).
Port forwarding is set as from wan to this device enable;
from lan to this device enable.
Microcontroller is connected to WAN, PC is connected to LAN. (other way around gives the same result)
when I ssh to GL through LAN IP I cannot ping the microcontroller from the GL.
I also cannot ping WAN static IP from PC.
This would be good enough if I dont actually need to monitor traffic from GL itself …

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