I was having problems with the internet at home recently. As soon as you turned on certain devices (usually the xbox, which is wired) it would crash the whole network.

I thought assigning static IPs and port forwarding might eliminate a potential cause, but then I found out that it wasn’t possible on my absolute POS router, so I decided to buy some decent kit to see if that would work.

I’ve now got a Draytek Vigor 120 modem, running as a PPoPA to PPoPE bridge to an Asus RT-N66U (Dark Knight) router.

Everything seemed to set up fine. I’ve left the 2.4ghz and 5ghz bands under seperate SSIDs and all tablets, phones and laptops connecting in via wifi are working great.

However, whenever I turn on the xbox 360 (which is wired) the whole network hangs.

Also, whenever I turn on my chromecast, I can stream local files from my tablet, but it crashes internet access.

As soon as I turn off the xbox or chromecast (whatever one happens to be on), everything goes back to normal.

Completely stumped since my knowledge of such things is limited to what I can learn online, and I don’t know where to start with this.

Can anyone even point me in the general direction of what could be causing this so that I can go off and research it?

Have you tried replacing the cable between the xbox and the router. I know it sounds basic, but you need to start from the bottom up. A damaged cable can cause very odd behaviour.

Also, when you say the network ‘hangs’ is that your local network or access to the net or both? Can you still ping your local router from a pc when the xbox is on and the network hangs?

Thanks matt. I’ve tried changing the xbox cable, no joy.

When I turn on the xbox, all access to the internet hangs from all devices and the xbox won’t log in to xbox live.

I can still access my router from any device on 192.168.1.1 without any difficulty, regardless of what other problems i’m having on the network. It always remains responsive and never crashes itself.

You mentioned you’ve assigned static IP addresses to the devices on your network, can you list what IP address each device has along with the internal IP address(s) assigned to your router?

Thanks.

Can you / have you reset the network settings on your Chromecast and XBox? I take it everything is set to get a DHCP address from your router?
RM.

A list of each device, its IP, and how it gets that ip would be a good start. Include the modem and router.

And check they’re what you think they are (ping or otherwise).

No VPN getting in the way? I have a home network, started allocated addresses from 1, which was OK until the device address was .10 which was my work VPN access IP 🙂

plug the xbox cable into a laptop and see what happens?

You mentioned you’ve assigned static IP addresses to the devices on your network, can you list what IP address each device has along with the internal IP address(s) assigned to your router?

I’ve gone back to default settings for the moment, so no static IPs.

Can you / have you reset the network settings on your Chromecast and XBox? I take it everything is set to get a DHCP address from your router?

I’ve tried resetting all settings on the xbox, chromecast and router a number of times, it doesn’t seem to help.

A list of each device, its IP, and how it gets that ip would be a good start. Include the modem and router.

All DHCP at the moment…when i get home I can put up a screenshot of the live devices on the network, there’s a detailed summary on the routers config page.

Have you checked if you have more than one DHCP server running? On my home network my son set up his RasberryPi and enabled DHCP on it and all hell broke lose (networking wise rather than the gates of hell opening in my lounge).

Did you have the issue you’ve described with your Chromecast on your old network kit too?
RM.

Have you checked if you have more than one DHCP server running? On my home network my son set up his RasberryPi and enabled DHCP on it and all hell broke lose (networking wise rather than the gates of hell opening in my lounge).

hmmmm, I do have a raspberry pi hooked up and running XBMC but I haven’t used it for months. I had completely forgotten about that! Doh! I’ll try disconnecting that when i get home and see if it sorts it out. 😳

Did you have the issue you’ve described with your Chromecast on your old network kit too?

Chromecast issue is a new one, since I bought the new kit.

It does sound like a second device is trying to act as a DHCP server. I had a very similar problem last year. Came back from holiday, powered everything back up including a NAS drive I don’t normally use. Couldn’t get any internet access (but could still see the router as you can and it told me I had a broadband connection). Eventually figured out that the NAS was acting as a DHCP server. Unplugged it, reset everything and it’s been fine ever since…..

Actually, I don’t think the Pi is hooked up to the router (it’s ethernet only).

I’ve got a NAS but I’ve not had it hooked up since getting the new kit.

How long does it take to crash? If it’s almost instantly, then DHCP seems unlikely, as it will take a while (hour or more) for the DHCP leases to expire.

Can you put a PC on your network and check network settings (“ipconfig /all” in a cmd if windows) before and after.

But if it’s crashing immediately, I wonder if you’ve got some kind of loop in your network somehow, e.g. an ethernet cable connected to two ports of a switch.

To diagnose that, you could try running wireshark on a tame PC and sniff the traffic.

https://www.wireshark.org

With the chromecast and xbox off all other devices function normally.

As soon as I turn on either the chromecast or xbox the internet access immediately crashes.

I’ll try pulling the whole network apart again and gradually rebuilding it, along with your wireshark suggestion 🙂

How long does it take to crash? If it’s almost instantly, then DHCP seems unlikely, as it will take a while (hour or more) for the DHCP leases to expire.

Duplicate IP addresses will, theoretically, cause both duplicate devices to fall off the network.

I think I’d start again, disconnect everything, switch off the wireless, then reintroduce devices one at a time.

Make sure any static IP addresses you are using are outside of your DHCP range.

Switch everything off that you know about and then look on the Asus, it will show you what’s connected (refresh device list). Could be something running somewhere that you’ve forgotten about, Pi, TV, NAS, Neighbour! etc.

the internet access immediately crashes

You could do with being a bit more specific than this.

When the internet “crashes”:

Can you ping the router?
The modem?
Other devices on the network?
Do you have a valid IP still?
Can you connect a new device and receive a valid IP?

Is the xbox connected to both wireless and ethernet and is somehow bridging the two interfaces?

1) Knock the xbox out of the equation. Plug the 360 in to the modem and make sure that you can get on to xbox live.

2) if 1 works, test without wireless. Plug the xbox in to the router as the only device on the network.

3) if 2 works, plug a laptop or something in with a network cable and see if you have the xbox and the laptop on at the same time

4) if 3 works, turn wireless back on and try the same laptop over wireless.

One variable at a time 🙂

Download superscan V3 from this link

http://www.mcafee.com/uk/downloads/free-tools/superscan.aspx

Unplug everything Ethernet based

Scan your network to see which IP addresses are in use , the tool should give some info on the devices

Turn off wireless and plug the ethernet devices back in and run the scanner again to see if there are any duplicates

Some AV software will delete superscan so turn it off before installing

OK, firstly I’ve turned off DHCP on the modem (which I had forgotten about).

I’ve tried hooking the Xbox directly into the modem and inputting my ISP settings into the xbox 360…it works. I can connect to xbox live if I go straight through the modem.

So that means it’s a problem with the router?

I’ve got up to date firmware and have tried a static IP and port forwarding for the xbox. No joy.

As soon as I hook the xbox up to the router and turn it on it won’t connect to xbox live and no other device on the network can access the internet. The INSTANT I power down the xbox all other devices start working instantly.

Have you tried a laptop in the same port?

If you’re plugging straight into the ‘modem’ and getting to the internet, then its routing.

I wouldn’t expect this to happen.

Can you describe how you’re doing this in more detail?

Have you given the Xbox the same IP as the router?

Static IPs are, generally, evil.

Also,

OK, firstly I’ve turned off DHCP on the modem (which I had forgotten about).

Are the modem and the router both DHCP servers?

You need one DHCP server, and any static IPs you assign (why?!) need to be outside the DHCP scope.

Have you checked the IP address of every device for conflicts?

Are you asking for advice and then ignoring it and making things up?

To further what Cougar says, pf, can you list all the devices, which ones have static addressing, what those addresses are, and what DHCP servers are running? I know its a PITA but its necessary info.

Some DHCP servers will gracefully check to see if an address is in use before assigning it, but its uncommon.
No offence, but you’ve not really helped us to help you…..

If you’re plugging straight into the ‘modem’ and getting to the internet, then its routing.

I wouldn’t expect this to happen.

Can you describe how you’re doing this in more detail?

Just to reiterate my OP… I’ve now got a Draytek Vigor 120 modem, running as a PPoPA to PPoPE bridge to an Asus RT-N66U (Dark Knight) router. Two completely separate devices.

The Vigor acts as a PPoPE bridge, it’s not a router, it’s a pure ADSL modem. The Asus handles the ISP credentials.

As scaled suggested, I tried hooking the Xbox directly into the modem, which meant I needed to add in my ISP connection details to the network configuration on the xbox. That worked fine. Which I think means the problem lies with my router.

Are the modem and the router both DHCP servers?

There is an option in the Vigor which allows you to disable the DHCP server function of the modem. On the basis that the router is also acting as a DHCP server and since jate suggested that two devices trying to act as DHCP servers could be causing a problem, I deactivated it.

Here is a screen shot of the option on the modem below (not my settings, just a random internet pic)

You need one DHCP server, and any static IPs you assign (why?!) need to be outside the DHCP scope.

Since I’ve deactivated the DHCP server on the modem, I now have one DHCP server…on the router.

I just tried assigning a static IP to the Xbox since I’m trying absolutely anything I can think of to make it work. It no longer has a static IP assigned since it didn’t work and I reset it.

Have you checked the IP address of every device for conflicts?

Yes. There are none. The only devices on the network while I’m doing any of this are the Xbox and occasionally a PC laptop to access the router.

To further what Cougar says, pf, can you list all the devices, which ones have static addressing, what those addresses are, and what DHCP servers are running? I know its a PITA but its necessary info.

I have absolutely no static addressing on the network now. I reset everything after that didn’t work.

The only DHCP server running is the one on the router, I have disabled the one on the modem.

I’ve just taken a screen shot of the only two devices on my network at the moment.

It’s it cos you’ve set for manual dns and then not provided any ip’s?

I’ve got the option “Connect to DNS Server automatically” ticked “yes”?

But on the router you’ve not given a dns address?

I’m not an expert, btw.

So there’s nothing whatsoever addressed statically now, and the only DHCP server is the router, and all devices are going via the router and the router alone?

Yup.

I’ve been trying everything I can to identify the issue and something VERY bizarre has just happened…

Xbox is wired to router.
Xbox HDMI goes to an AV receiver and then an HDMI goes from the AV receiver to my TV (bog standard LCD, bog standard AV receiver, no wifi or smart stuff)

When I turn on the xbox and the AV receiver, my internet on my laptop still works.

It’s not until I turn on the TV that things start crashing??!!

I’ve just tried connecting the xbox directly into the TV and when the xbox is on everything is fine, but again, as soon as a turn on the TV the network crashes and I can’t access the internet. As soon as I turn off the TV the internet works fine again.

wtf??

Internet works fine when just the TV and AV receiver is on. Problem seems to be when the TV AND XBOX are both on.

Could some sort of electromagnetic problem from my TV cause this?

Or is this just a red herring and the xbox doesn’t fully activate until it detects an hdmi connection?

Interesting….is it a “Smart” TV? Or indeed a ‘smart’ AV receiver?

Sorry, you said its not a smart telly- apols.

Any Powerline adapters running here?

No powerlines adapters.

I’ve just stripped absolutely every single media connection out in my house now!

Going to start from the ground up in case it’s even something as basic as a faulty device/socket etc that’s throwing things off.

Yeah- good idea. I was leading up to trying to work out whether a broadcast storm was killing everything, it certainly sounded like one. But its a dumb telly…..

I guess I would just make sure that nothing is looped back into any other things, which is a bit captain obvious I know.