Steam Brings Down Entire Network

[Hank Chill]

So I noticed some very unusual behaviour coming from my network, and have found Steam to be the culprit. Looking to the forums to see if anyone has similar experiences or solutions.

I had to redownload a large game (Fallout 4), no big deal, starts to download as normal. As of late, the download speeds from Steam have not been hitting anywhere near what my network is capable of. The download speed has been maxing out at 11MB/sec, where my ISP is capable of delivering up to 40MB/sec. When the 11MB/sec threshold gets hit, my whole network becomes unresponsive. No connected system can get online (no internet access) or even talk to each other -- I can't even connect to my router's IP address, it just hangs indefinitely, and Chrome throws a DNS probe issue.

The moment I pause my Steam download, everything comes back online. Internet works, computers can talk to each other again, everything runs like normal. Curious, I resume the download. The download maxes out at 11MB/sec and continues downloading, and the entire network becomes unresponsive again. Again I pause it so Steam stops downloading, and the network comes back up.

Wondering if it's my network, I ran some transfer tests using different amounts of bandwidth. Using constant transfer speeds over the internet of 1 to 40MB/sec, everything is stable. All other devices in the house remain online and accessible, and can still connect to the internet with no issue. I tried different applications as well that can perform high speed downloads, and had zero issues.

The moment I started the Steam download and it hit 11MB/sec, again, entire network becomes inaccessible. I had to change the Steam bandwidth settings to cap out at 7MB/sec so it doesn't hit that threshold and cause my network to go unresponsive. With the bandwidth cap in place, the network remains online when Steam downloads -- not the most ideal configuration since I have a 320Mbit connection and would want to utilize that when I can.

What could Steam possibly be doing that could be causing this? I'm thinking of running a wireshark trace on Steam's connections to log exactly what is happening. What is even more curious is that while the entire network becomes unresponsive, Steam continues to download, and becomes the only thing that has connectivity, and remains that way until the download has completed or paused.

My network equipment is also no slouch; I run a gigabit network that can more than handle these piddly outbound/inbound internet transfer speeds ;)

Anyone seen the same kind of issues? Done anything to get around these issues besides lowering the Steam bandwidth usage?

[MaddDoktor [Linux]]

Is your computer connected by Ethernet or wireless and what do you get when you run a test at someplace like speedtest.net? Wireless is like a hub where if more than one thing tries to communicate at the same time, data can collide and have to be resent.

In my experience doing some testing at work with 50/10 Mbps cable (typically tests ~58/11.7), it probably works best if your wireless speed is at least 3 times your Internet speed. For example when our access point was out in our warehouse and I only got 78 Mbps wireless-n speed, it speed tested at ~25/11.7. When I moved the access point into our office and got 150 Mbps wireless-n, it speed tested about the full 57-58/11.7 Mbps.

Even if using Ethernet, maybe some nic on your network is not fully compatible with gigabit (which you would need to get the 320 Mbps you say your Internet is). I had a 10/100 card once that would not even properly autonegotiate 100 Mbps on a 10/100 network, it would go into a frenzy resulting in 25% packet loss in ping tests. So I had to force the nic down to 10baseT (it could do full-duplex with no problems at that speed).

[Crowsfoot]

Check a download test at testmy.net, if its reaching 11MB or close to it, then you have an ISP issued cap/possible contention. If you have non-commercial internet, contention is common during peak time. Check you contract to see if it mentions peak time contention policies.

Failing that, if testmy.net is reaching your ISP issued speed you signed up for then something else is causing a problem, your router most likely being the culprit as others have mentioned.

[Hank Chill]

Originally posted by fauxtronic:

It's almost certainly your router struggling to cope with the increased throughput. Are you using the router given to you by your ISP or have you bought your own? I've got quite the collection of cheapo ISP routers dating back to 2002 which have never been used because I always use my own (presently a quad core Asus router).

You could try power cycling your router I suppose. Memory leaks can also become evident when a router hasn't been rebooted in a while... and issues like this are sometimes the outcome.

It's definitely not the router. As I mentioned in my storybook post, the router does not struggle on normal occasion; doing many download/upload test cases, I can set all the computers in my house to hammer the internet, and the network will stay up, as well as have bandwidth to spare. I don't use the craptastic ISP routers -- those things are awful. I use an ASUS RT-N66U gigabit router; using 320Mbit isn't even half of the throughput it can handle. Steam is using only a fraction of what I hammered the network with, and caused the network to bomb.

Power cycling doesn't fix the issue, the issue is stemming from something that Steam is doing. My router is also on an auto-reboot schedule once a week to ensure memory leaks are kept to a minimum.

Originally posted by MaddDoktor Linux:

Is your computer connected by Ethernet or wireless and what do you get when you run a test at someplace like speedtest.net? Wireless is like a hub where if more than one thing tries to communicate at the same time, data can collide and have to be resent.

In my experience doing some testing at work with 50/10 Mbps cable (typically tests ~58/11.7), it probably works best if your wireless speed is at least 3 times your Internet speed. For example when our access point was out in our warehouse and I only got 78 Mbps wireless-n speed, it speed tested at ~25/11.7. When I moved the access point into our office and got 150 Mbps wireless-n, it speed tested about the full 57-58/11.7 Mbps.

Even if using Ethernet, maybe some nic on your network is not fully compatible with gigabit (which you would need to get the 320 Mbps you say your Internet is). I had a 10/100 card once that would not even properly autonegotiate 100 Mbps on a 10/100 network, it would go into a frenzy resulting in 25% packet loss in ping tests. So I had to force the nic down to 10baseT (it could do full-duplex with no problems at that speed).

All computers are connected via Ethernet. Every PC has a Gigabit NIC, but even if it didn't, it wouldn't change the fact that Steam causes the network to fail, as *every* device in the household, wireless or not, is unable to connect to the network, as Steam pretty much kills connectivity at the Router level.

Originally posted by Muryαñi:

Check a download test at testmy.net, if its reaching 11MB or close to it, then you have an ISP issued cap/possible contention. If you have non-commercial internet, contention is common during peak time. Check you contract to see if it mentions peak time contention policies.

Failing that, if testmy.net is reaching your ISP issued speed you signed up for then something else is causing a problem, your router most likely being the culprit as others have mentioned.

Speedtest.net gives me between 250Mbit-320Mbit every time. Again, isn't an ISP or Internet issue, it's Steam that is killing the router when it passes a speed threshold.

I should totally take a video of what is happening -- it's crazy and makes no sense. It looks like I just might have to wireshark it and go through the logs to see what Steam is doing that is killing my router.

[Crowsfoot]

What happens if you download via steam on another computer on the same network? Also just for kicks what happens if you change your DNS setting to 8.8.8.8 which is googles DNS or even Open DNS on either
-208.67.222.222
-208.67.220.220

Edit:
Check these settings as well, just in-case, it seems like this may be something internal to your network or adapter configurations.

Start > Control Panel > Network Connections > Right Click Your Network and Choose Properties > Advanced Tab >

Now Just Make SURE both boxes under Internet Connection Sharing are NOT Checked. (if the one on the bottom is, check the one on the top then uncheck the bottom, then uncheck the top)

This should solve your problem.

[wuddih]

Originally posted by Hank Chill:

It's definitely not the router. As I mentioned in my storybook post, the router does not struggle on normal occasion; doing many download/upload test cases, I can set all the computers in my house to hammer the internet, and the network will stay up, as well as have bandwidth to spare. I don't use the craptastic ISP routers -- those things are awful. I use an ASUS RT-N66U gigabit router; using 320Mbit isn't even half of the throughput it can handle. Steam is using only a fraction of what I hammered the network with, and caused the network to bomb.

the bandwidth is not the problem and probably never will be. the thing that the router or better, the router firmware cannot handle is the amount of connections that Steam initiates to do its downloads and might drop the connection for several reasons. one really common reason is, the router security implementation might think it is some form of attack and blocks the whole subnet from the source of the attack.

so you might wanna boggle around with some security settings ... or switch to other firmware like dd-wrt.

[Hank Chill]

Originally posted by Muryαñi:

What happens if you download via steam on another computer on the same network? Also just for kicks what happens if you change your DNS setting to 8.8.8.8 which is googles DNS or even Open DNS on either
-208.67.222.222
-208.67.220.220

Edit:
Check these settings as well, just in-case, it seems like this may be something internal to your network or adapter configurations.

Start > Control Panel > Network Connections > Right Click Your Network and Choose Properties > Advanced Tab >

Now Just Make SURE both boxes under Internet Connection Sharing are NOT Checked. (if the one on the bottom is, check the one on the top then uncheck the bottom, then uncheck the top)

This should solve your problem.

I don't think it's a DNS issue -- I can't reach the router when Steam kills the network, so it doesn't get to the point where it can go from Router -> DNS -> Outbound.

Also my internet connections are not shared.

Originally posted by wuddih:

the bandwidth is not the problem and probably never will be. the thing that the router or better, the router firmware cannot handle is the amount of connections that Steam initiates to do its downloads and might drop the connection for several reasons. one really common reason is, the router security implementation might think it is some form of attack and blocks the whole subnet from the source of the attack.

so you might wanna boggle around with some security settings ... or switch to other firmware like dd-wrt.

It's a good theory, but if that was the case, then the Steam download would stop too if the router was blocking an attack, since the "attack" is coming internally and all systems are on the same subnet, therefore killing the Steam connection.

I am going to try a couple more things still; I'll change the download server manually to a different one and see if that makes a difference. I also can try downloading something on my son's PC too, see if the same issue occurs.

It's still bizarre as it's only happened since the last Steam update; never had any issues before then.

Off to try a few more things :)

By the way, have any of the commenters been able to pass 11MB/sec download speed on the latest Steam update without issues?

[Crowsfoot]

Have you run a 'tracert' / 'pathping' test with Steam off, then again with steam on. You already know the network goes down, the case is what is the cause/where, might give an indication as to whether its your router or a hop outside of your network.

My hunch is your router doesnt like something, you could try ruling it out if you have another lying around, any will do for a quick test.

Are all steam dependant ports open?

[MancSoulja]

You're confusing megabit and megabyte. The speedtest you ran, gave you a result in megabit (Mb) steam shows your download in megabyte (MB) 11 MB\s is 88 Mb, you're maxing out your bandwith, that's why your other devices are going offline.

[Crowsfoot]

Originally posted by MancSoulja:

You're confusing megabit and megabyte. The speedtest you ran, gave you a result in megabit (Mb) steam shows your download in megabyte (MB) 11 MB\s is 88 Mb, you're maxing out your bandwith, that's why your other devices are going offline.

Oh god yeh you're right, I think you've solved it xD

[Hank Chill]

Originally posted by Muryαñi:

Have you run a 'tracert' / 'pathping' test with Steam off, then again with steam on. You already know the network goes down, the case is what is the cause/where, might give an indication as to whether its your router or a hop outside of your network.

My hunch is your router doesnt like something, you could try ruling it out if you have another lying around, any will do for a quick test.

Are all steam dependant ports open?

I'm doing a ping test to my router before downloading and after initiating a download. There's definitely something funny going on, as before I initiate a download, the router response is <1 sec. Once Steam hits the good ol 11MB/sec the response time goes between 30-40ms. The moment the download stops, it's back to <1ms and network comes back.

Steam must be doing something to the router, still need to wireshark that bad boy, as well as test on my son's PC to see if his causes the router to go on the fritz as well.

Originally posted by MancSoulja:

You're confusing megabit and megabyte. The speedtest you ran, gave you a result in megabit (Mb) steam shows your download in megabyte (MB) 11 MB\s is 88 Mb, you're maxing out your bandwith, that's why your other devices are going offline.

Nobody is confusing anything here; if my speedtest hits 320Mbit (40MB/s) and Steam only hits 11MB (88Mbit), and my entire wired network has Gigabit connectivity, then how can you possibly come to a claim that I'm maxing out my bandwidth xD Besides, even if I *was* maxing out my bandwidth, I should still be able to connect to my router's configuration, which dies when Steam downloads. Did you even read the previous posts? :P

Here, speedtest results that rule out a bandwidth issue ;)
http://www.speedtest.net/my-result/5366329058

Originally posted by Muryαñi:

Oh god yeh you're right, I think you've solved it xD

You're being sarcastic, right, because nothing is solved :D

If all else fails, I may go the custom firmware route on the router.

[Darren]

Check what monitoring tools your router has on it. It is possibly Steam is maxing out your upstream bandwidth which would kill all your connectivity as you need at least some upstream bandwidth.

[Hank Chill]

Originally posted by Darren:

Check what monitoring tools your router has on it. It is possibly Steam is maxing out your upstream bandwidth which would kill all your connectivity as you need at least some upstream bandwidth.

Already checked. Connectivity to the router completely dies when Steam hits 11MB/sec download. I watched the realtime traffic monitor while Steam started to download, and once it hit the 11MB/s threshold, the connection to the realtime traffic monitor stopped.

There's no logical reason why Steam would be maxing anything out, as when the traffic monitor was running it was only using 1% traffic and then stopped responding. Plus this has never been an issue before up until a week ago.

Clearly nobody else has experienced this type of behaviour, looks like I'm on my own to try and solve it. As a workaround, I just limited Steam's download bandwidth to 7MB/sec.

[The Giving One]

The first step in order to properly troubleshoot connectivity issues is to bypass the router and use ethernet only and disconnect all other wireless devices from the network. Eliminate the router from the equation, unless you already have.

https://support.steampowered.com/kb_article.php?ref=1456-EUDN-2493

Troubleshooting Network Connectivity Issues

Please follow the steps below to diagnose network connectivity issues within Steam:

Test Your Router
Before trying anything else:

Try bypassing your router by connecting your computer directly to your modem.

If the issue disappears after bypassing your router, please refer to the Using a Router with Steam topic for instructions on configuring your router.

Next, boot your computer into safe mode WITH networking and troubleshoot Steam from that safe boot. You can post from that safe boot as well.

[Granin]

Connect to your router via ssh/telnet and run a "top" command and keep it running. Then try to download something via the Steam client and see if your %id is 0 or load average higher than 1. If that's the case then make sure you didn't set port forwarding for ports Steam uses otherwise such traffic is bypassed by CTF kernel module ("NAT acceleration") and that traffic is processed by the Linux kernel, thus router's CPU which is too weak to handle it. Using your router in order to achieve higher WAN throughput than 100 Mb/s, NAT acceleration must be fully working and all incompatible features turned off (i.e. traditional QoS, per IP address traffic monitor etc).