Too many connections causes router to stop responding for one computer?

[bigzdog]

AC56R
Firmware tried with same issue
Merlin 380.65
Merlin-LTS 22E4
Stock 3.0.0.4.380.7266

ISP Comcast 85mbps

Recently replaced my old E2000 running Tomato USB Shibby with the AC56R running firmwares listed above. I have also cleared the NVRAM after each firmware upgrade.

Problem: I attempted to download about 40 1GB files using my download manager. Each file had 10 connections to the server totaling ~400 connections.

After 5-10 minutes downloading this, all downloads stopped and timed out. I was not able to navigate to any webpage in my browser, or even bring up the router web interface via IP. Would just spin loading.

I can ping my router during this time. I can ping any website successfully and the DNS lookup works properly. I cannot load any pages through any browser. Chrome FF or IE

This problem persists until I either reboot the computer or the router. I have tried unplug/replug network cable, but no good, only a reboot.

I can reliably recreate this issue by attempting to download any files in great enough number.

I am able to successfully download the files if I limit either the number of simultaneous downloads or limited number of connections per file. Seems to be related to the number of total connections?

I have this same issue with 3 different devices in my network I tested. All were running Win10, not sure it matters. It only affects the device that was downloading the files. Other devices are not affected and can continue to browser the web.

I regularly downloaded files this large and larger and in greater number with my old E2000 with no issue so it must be something with the Asus router, but I am unsure of what it could be.

400 connections should be nothing for this router. Have any ideas?

 

[joegreat]

AC56R
Firmware tried with same issue
Merlin 380.65
Merlin-LTS 22E4
Stock 3.0.0.4.380.7266

ISP Comcast 85mbps

Recently replaced my old E2000 running Tomato USB Shibby with the AC56R running firmwares listed above. I have also cleared the NVRAM after each firmware upgrade.

Problem: I attempted to download about 40 1GB files using my download manager. Each file had 10 connections to the server totaling ~400 connections.

I get the same issue with my ISP (UPC in Europe with a Ubee modem) when I do Torrenting with to many connections.

Based on my try and error finding I am save up to 200 seeding connections. When it comes to downloading I need to limit my self to a much lower number of connections (~50) to survive - and of course I have limited also the bandwith.
The funny thing is that the Torrenting continues to work without problems but all other internet activities are stalled (or very slow).

The only help is to reboot the modem (and the router in my case) to get back normal Internet connectivity - restarting the router alone does not help.

This issue was discussed in other cable ISP related forums and the conclusion was that the ISP does this "limitation" on purpose as they to not want you to do Torrenting on their unlimited Internet lines (actually forbidden to have a server kind of setup in their Ts&Cs)!

 

[bigzdog]

Based on my try and error finding I am save up to 200 seeding connections. When it comes to downloading I need to limit my self to a much lower number of connections (~50) to survive - and of course I have limited also the bandwith.
The funny thing is that the Torrenting continues to work without problems but all other internet activities are stalled (or very slow).

The only help is to reboot the modem (and the router in my case) to get back normal Internet connectivity - restarting the router alone does not help.

This I would understand. My issue seems to be something only between the computer downloading and the router. It never affects other clients.

1. My old E2000 router never had a problem, no other changes to network besides swapping router
2. Other devices continue to work fine while the device that was downloading cannot go anywhere on internet until rebooted.

These lead me to believe it is not a modem/ISP issue

Besides this problem, the router is a huge improvement in everything else, specifically wireless range and speed over the old E2000

 

[john9527]

and speed over the old E2000

You could possible be tripping an ISP filter because of the router improvements that you didn't hit with the E2000???....in which case the ISP may be killing the ports that are opened by that particular client..

 

[bigzdog]

You could possible be tripping an ISP filter because of the router improvements that you didn't hit with the E2000???....in which case the ISP may be killing the ports that are opened by that particular client..

I wondered about that. I meant wireless speed in above quote. WAN Speed is the same on both routers, right around 90mbps, which is the same if I plug directly into modem.

However, that doesn't explain why the downloading computer cannot access router web interface or why other devices are unaffected.

I would think if the ISP was blocking in some way or a problem with modem, all devices would be affected. Also the ISP wouldn't be able to kill all ports open?

To be clear, I am not torrenting, these are files from an FTP server, but I have also tried downloading many linux ISO from various http/ftp servers as a test and it also dropped connection. Once the internet drops. I cannot browse to any website so I don't know if the ISP could selectively kill web browsing for one client behind a firewall.

 

[john9527]

I would think if the ISP was blocking in some way or a problem with modem, all devices would be affected.

Not necessarily....they could just hang a currently open 'offending' port so that it would hit only the one client.

That you can get to everything from other clients suggests that nothing is seriously hung up in the router, but I agree it's ambiguous as to who is the cause.

EDIT: Probably the only way to track it down would be to do a trace and see what's actually happening. Somebody with more expertise then me would need to help out with that one.

 

[bigzdog]

Not necessarily....they could just hang a currently open 'offending' port so that it would hit only the one client.

That you can get to everything from other clients suggests that nothing is seriously hung up in the router, but I agree it's ambiguous as to who is the cause.

The thing that really stands out to me and makes me think it is not modem/ISP related, is the downloading client cannot browse to the router web interface after dropping connections, just sits and spins, while other clients can. Like it is something on the router blocking/stopping the client, but I don't know what it may be.

 

[atkinsom]

Maybe DMZ the client as a test and see what happens. In theory the router wouldn't touch the client and allow all activities. Just a thought as a simple test.

 

[john9527]

Just for interest....if you are running the Merlin build or my fork, on the Tools page, it will tell you the total number of connections and active connections.

 

[joegreat]

Just for interest....if you are running the Merlin build or my fork, on the Tools page, it will tell you the total number of connections and active connections.

In my case (working well with limited to 200 torrent connections) it shows:
Connections 1454 / 600000 - 303 active

 

[bigzdog]

Just for interest....if you are running the Merlin build or my fork, on the Tools page, it will tell you the total number of connections and active connections.

EDIT: Missed it the first time around, but here is what you were asking for. This is while the downloads were running.

1052 / 300000 - 589 active
------------------------------
Currently running Merlin build and it doesn't seem to have as much information as your build, but I found a list of connections under System Log -> Connections. Lists each connection as TIMEWAIT ESTABLISHED, etc.

Before starting any downloads I had 226 connections in this list
After starting download, connection dropped almost immediately so I had to use another device to access router. I had 573 connections and about half of those were in ASSURED state.

 

[sfx2000]

Most of the torrent issues are related to memory in the Router/Gateway - turn down the number of connections - and one can play with the torrent client settings there.

Even on the desktop - I keep things limited...

 

[bigzdog]

Running LTS 22E4
Also tested Tomato Shibby and had the same problem
Although they may be similar, I just want to repeat I am not torrenting. These are simple HTTP downloads, not sure if torrenting would cause this issue also.

Done some more testing and have taken connections in download manager down to 50 total. 5 simultaneous downloads with 10 chunks each.

Even this low number will cause me to be unable to browse anywhere on Internet or even to Router web interface. However it does take longer for this to occur.

I guess because the downloads are HTTP on port 80, it makes sense that when they start to fail, I also cannot browse anywhere. It is like the router stops all port 80 traffic for only 1 computer. Other computers on the network can still browse fine including the router web interface.

Previous router E2000, I could run 400 total connections (which was the limit for my download manager) for hours and have no problem.

I am at a complete loss as to why this is occurring and why it only.

 

[System Error Message]

on my mikrotik router i have no issues having thousands of connections

a few hundred connections shouldnt make full use of memory. The problem seems to be either the router being fully taxed or lack of QoS to prevent WAN from being fully utilised by just the torrent itself.

 

[bigzdog]

on my mikrotik router i have no issues having thousands of connections

a few hundred connections shouldnt make full use of memory. The problem seems to be either the router being fully taxed or lack of QoS to prevent WAN from being fully utilised by just the torrent itself.

Haha, even my E2000 with 300mhz cpu and 32mb RAM would be more reliable. This many connections, the cpu would be 100%, but it would keep chugging along.

Not torrenting, just HTTP downloads and I can watch TCPVIEW, all port 80 connections.

Strange thing is it only affects the computer downloading. Other computers in network aren't affected so it doesn't seem like the modem/ISP.

Something on the router that drops all port 80 traffic for one machine? Is there any kind of protection built into this router that may be tripping?

NVRAM reset router to default settings and only have basic settings set but still the issue.

 

[ColinTaylor]

As it is confined to the individual PC that is doing the downloading, have a look in the Windows Event Viewer for any clues.

 

[System Error Message]

Haha, even my E2000 with 300mhz cpu and 32mb RAM would be more reliable. This many connections, the cpu would be 100%, but it would keep chugging along.

Not torrenting, just HTTP downloads and I can watch TCPVIEW, all port 80 connections.

Strange thing is it only affects the computer downloading. Other computers in network aren't affected so it doesn't seem like the modem/ISP.

Something on the router that drops all port 80 traffic for one machine? Is there any kind of protection built into this router that may be tripping?

NVRAM reset router to default settings and only have basic settings set but still the issue.

for me the CPU wouldnt be at 100%, 36 cores capable of making use of 10Gb/s internet which in the UK would be decades away. Despite how much i load the CPU it doesnt use more than 1 core with my connection speed.