Problem when one computer is connected by Ethernet to the router

[gee]

Hello,

I have an issue with my current Asuswrt-Merlin router.
It is an Asus RT-AC68U (by T-Mobile if that matters).

To be fair, I had the same issue with another router on Tomato, so it's not just Merlin's at fault...

My issue is that when I plug in the router my main computer by Ethernet, my laptop cannot connect by WIFI anymore, my tablet has a barely usable WIFI connection (and my cellphone's seems slower). As soon as I unplug the cable from the port, it's all fine.
My laptop is 801.11g, my tablet and phone n connected on the 5Ghz band.

I've tried with different cables so I know it's not the cable (and with another router so I know it's not the router...)
I don't seem to have an issue if I plug my laptop in the router using Ethernet either.
I don't seem to have an issue if I connect my desktop to my old router, and then that one to my Asuswrt-Merlink (but I just tried so maybe later?).

The desktop computer has no connectivity issue though....

What does that mean?
Is my Ethernet port busted?
Is my OS badly configured somehow (it's Arch Linux)?
Is there any settings to tweak on the router?

I actually switched to Ethernet for the Desktop as wireless was too unstable (although that was with my previous router.... maybe the new one would be fine, but I don't have any 5Ghz PCI or USB adapter :/)

Thanks!

 

[Marc66]

My first thought would be to look at IP or MAC address conflicts.


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[gee]

Hello Marc66,

I've looked at my desktop's MAC against the ones currently connected and none is a match.
As for IP, it seems fine and all DHCP (though I have saved some in the Manually Assigned IP in the DHCP tab). Should I play with that?

Thank you!

 

[john9527]

My first thought would be to look at IP or MAC address conflicts.

Or Computername conflicts. You can't have two systems with the same name on the network at the same time.

 

[gee]

Hello john9527,

well that shouldn't be the case, BUT the problem computer does have the same name as the SSID of the router.
Could that be it? (though I don't see why it would matter with a cable and not wireless...)

Thank you!

 

[hardtotell]

Only as a last resort and if there's no reasonable explanation for why it is happening, you can reset the router back to the factory defaults AND do not restore any previously saved settings files. Sometimes the NVRAM settings inside the router can become corrupted and cause strange problems, especially with WiFi. It may seem a lot of tedious work to set the options manually, back to the way you had, but then you don't waste time chasing a ghost.

Before you reset the router, take screen shots of the router pages and paste them into a Word document to remember the settings.

 

[RMerlin]

To rule out any possible OS-specific issue, boot your laptop with a Linux Live CD, and see if the problem disappears then.

 

[gee]

Changing the pc hostname to something different from the SSID didn't help.
I'll try to boot a live distro or reset the modem (but having the same NVRAM issue on 2 routers would be strange...)

 

[TonyH]

Hi,
Take a look at network card advance settings.

 

[gee]

Hi,
Take a look at network card advance settings.

Hmmm, I don't see that in the router's webpage, where should I look for it?

 

[TonyH]

Hmmm, I don't see that in the router's webpage, where should I look for it?

Hi,
NIC in your main PC which is causing the trouble. For shot gun approach just replace the NIC to see what happens.

 

[gee]

I don't have another one, I am using the on-board of the motherboard if not you are right, I would have tried that.

 

[gee]

A little late but more info.
I got a new motherboard and no difference so the issue was not hardware related I guess.
The issue does not seem to always be there though.
Yesterday I removed the intermediate router and things seemed to work fine, but later at night I tried using my wireless devices and their connection was not working anymore... So I'm not sure about a live-cd unless I used it long enough...

 

[gee]

I think I've finally figured it out.
So if I'm correct this time, it was unrelated to the hardware or the router.
It seems my main PC's pulseaudio was flooding the network with multicast (for no good reason).
Disabling multicast in pulseaudio seems to do the trick.
Now I am not sure it worked sometimes and not others... but that seems good for now.

 

[gatorback]

I have upgrade two T-Mobile cellspots to become RT-AC68Us and have not seen these problems.

I am certain that if you called T-Mobile (assuming you are a customer in good-standing), they would swap it out for a good one. Restore the original firmware: http://tinyurl.com/asuscellspot

 

[gee]

Hmmm I don't believe it is related to the router itself, as I had a similar issue with my previous (linksys) router.