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utorrent destroying DNS lookup

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Feb 15, 2005
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utorrent destroying DNS lookup

Anyone know why/how utorrent can destroy my modem's ability to do DNS lookups? As long as utorrent is running, my Shaw Cisco wifi modem cannot do name lookups. Exiting the program will quickly bring up the DNS lookups again, so this affects all devices in the home.
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Technically the modem doesn't do the DNS lookups, the router does. It's possible that your Shaw combo unit has a really crappy low-performance router section that gets overwhelmed when you have too many connections going at once while torrenting. That may be the most likely explanation. You could limit the number of connections that uTorrent uses - try setting it to no more than 16.

As far as I know uTorrent can't change the DNS in the router, and you said it affects all computers on your network, but see if you can access the router via the web admin interface and check the DNS setting while you are having this problem to make sure they haven't changed (both the values, and whether the DNS server is enabled if the router has the option to disable it).

Check the computer running uTorrent to see if it has a primary and secondary DNS (adapter TCP/IP properties, or command window: "ipconfig /all"). Usually the default is to make the router the primary DNS, and one of your ISP's DNS servers the secondary DNS. If your computer or device was having trouble getting a response from the primary DNS, it should go automatically to the secondary DNS. If yours doesn't do that, there's something wrong with either your DNS settings or your router's ability to handle DNS traffic.

There's a standard DNS performance-testing utility called DNSBench that simply checks the lookup times of your default DNS and any other DNS you want to compare (like Google DNS, OpenDNS, your ISP's alternate DNS etc.) with a test suite of a few hundred common sites. You could run it before torrenting, just after starting a torrent, and while the torrent is running at full speed. That would give you more information about what's wrong.
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Jan 25, 2011
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Start using qBittorrent, you'll be forever happy.
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I'll have to look into the above. :)
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Feb 5, 2007
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Mississauga
Does old utorrent do that?
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Jun 12, 2003
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Markham
Get a stronger router

Torrenting used to destroy my old router as well... DNS queries would just stop working for some reason, requiring a reboot to get it back..

No more problems even with an old wrt54gl
ShadowVlican
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My guess is too many connections during torrents. Run a netstat - an from command prompt to see how many connections are open. Too many connections mean new connections won't work.

Change your router to modem only and get a router that can handle torrents. Check out smallnetbuilder for reviews.
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Markham
alkizmo wrote: Make sure this option is unchecked (It is checked by default).

It is a huge resource hog and has no purpose.

[IMG]http://i.imgur.com/2Qegcdf.png[/IMG]
Oh cool! Perhaps I can open even more connections now
ShadowVlican
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rf134a wrote: Anyone know why/how utorrent can destroy my modem's ability to do DNS lookups? As long as utorrent is running, my Shaw Cisco wifi modem cannot do name lookups. Exiting the program will quickly bring up the DNS lookups again, so this affects all devices in the home.
Change/adjust your global bandwidth rate limit (20%,30%...) to reflect your maximum upstream bandwidth.
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Mar 21, 2006
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Thornhill
It's not bandwidth, it's number of connections. When I used to use torrents, you could see as the number of open sockets went up, crappy routers became unresponsive.
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leeoku wrote: Does old utorrent do that?
The older versions did not destroy my dns lookup. I have uninstalled the latest version and reverted to 3.2.3 from 2013. It seems to be working fine.
ShadowVlican wrote: Get a stronger router

Torrenting used to destroy my old router as well... DNS queries would just stop working for some reason, requiring a reboot to get it back..

No more problems even with an old wrt54gl
I've upgraded my router 3 times. I had no problem for years with my trusty D-Link DIR-655. Then, that was upgraded to an Asus RT-N66 and now I'm using an Almond+.
alkizmo wrote: Make sure this option is unchecked (It is checked by default).

It is a huge resource hog and has no purpose.

[IMG]http://i.imgur.com/2Qegcdf.png[/IMG]
Cool, thanks
hightech wrote: My guess is too many connections during torrents. Run a netstat - an from command prompt to see how many connections are open. Too many connections mean new connections won't work.

Change your router to modem only and get a router that can handle torrents. Check out smallnetbuilder for reviews.
OpenWRT is showing 496 connections out of 16384.

qBittorrent worked once and never worked again. Strange. :(
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rf134a wrote: the latest version and reverted to 3.2.3 from 2013.
Well there's your problem. You shouldn't be using anything except for 2.2.1
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I lost all trust in uTorrent after the EpicScale bitcoin miner fiasco. The newest versions have too much bloatware too.
Heatware/HoFo upon request

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