Ubuntu

Zywalls Internet Connection gets killed when ubuntu computers download large things

Asked by kaefert

Zywalls Internet Connection gets killed when ubuntu computers download large things

Okey so this is about my internet connection @ the home of my girlfriend..
I've got a Zyxel Zywall2 which plays router for my network, and many of the clients are winows machines, which dont cause any problems.
When i connect ubuntu hosts, first everything works as it should, they get private ip-adresses assigned and can access the internet in every way. But when i do something that requires large downloads (more than some k) like installing software, or directly downloading something via a browser, it somehow kills the WAN connection of the Zywall. So not the LAN connection from the host concerned but the internet connection for the whole network.

The same phenemon also happens when performing downloads from virtual winxp pc's running in virtualbox on an ubuntu host. So I think from that you can tell that it is unrelated to the used software, but somehow connected to the basic networking of linux / ubuntu.

i cant think of anything that an ubuntu host could send while downloading stuff differently than a windows host - isnt a http-request always a http-request?!

i hope someone has a clue and can help me.

some more facts:
-) i've used differently ubuntu hosts, all running 7.10
-) the same ubuntu hosts dont cause any problem @ my home, with another one of the same router-make (zyxel zywall2) and the same internet provider (inode) - the only difference i see between the 2 sites is that @ my home the internet connection is "entbündelt" = independent from the austrian "Post" = "mail"?

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sno (sno-squee) said : 		#1

Hello there, this sounds like it may be IPv6 causing the problem with the Zywall router, some routers are not working with ipv6 at all or very well, you can test this by disabling ipv6 and see if the problem remains, it might be good to check for a firmware update for the zywall device also.

To disable ipv6 please check https://help.ubuntu.com/community/WebBrowsingSlowIPv6IPv4

hope this helps.

sno

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kaefert (kaefert) said : 		#2

Thanks for that hint sno, i disabled ipv6 by adding it to the blacklist @ /etc/modprobe.d/blacklist and rebooting afterwards, but it didnt change anything in the behavior of my internet connection

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kaefert (kaefert) said : 		#3

by the way - because the page you linked sayed that disabling ipv6 could be a solution for slower connections or slow dns resolution - but speed isnt a problem at all, the ubuntu hosts are just as fast as the windows xp hosts (and for smb they are even much faster).

the only problem is if i start downloading something via http or ftp the first 1 to 5 secounds works great (with great speed) but after that the internet connection for the whole network is down, and takes some seconds to get established again. sometimes even the zyxel zywall crashes and needs to be restarted to be functional again - but this happens only 1 of 10 times

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sno (sno-squee) said : 		#4

Hi there. Unfortunately that didn't seem to help, if the problem only exists with the first zywall router (at your girlfriend's house) , is there any way you can swap the 2 temporarily, to rule out the ISP being the problem? The only thing i can think of now is the router somehow being affected by the ubuntu systems, i have never seen this but you can swap the routers to test.

Also check for a firmware upgrade for the router in question from the manufacturers website.

Hope you get it fixed.

sno

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kaefert (kaefert) said : 		#5

the zyxel zywall that is now used is already a replacement for another router that produced the same problems.. so it seams the provider is somehow involved in the problem, but since all windows hosts work as they should, and the ubuntu hosts work as they should at my home, its somehow a combination of ubuntu and this internet connection at my girlfriends site..

are there any differences in the ip-stack of ubuntu compared to microsofts ip-stack?

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kaefert (kaefert) said : 		#6

okey so i again played a bit with the connection here and thats what i found out:

-) first i connected the internet modem directly to a ubuntu computer and connected to the internet via VPN - PPTP --> with this setup everything worked as it should

-) then i changed everything back (modem --> zywall --> localnetwork --> ubuntu computer) and the problem reappeard (if ubuntu downloads something bigger than some mbs, the internet connection of my zywall gets killed - but no problem if windows hosts download the same files)

-) one more thing i found out: if i disable the firewall part of the zywall, the problem is gone too! (only problem with that is that the firewall part is needed)

is there anyone reading this? and does one of you have any clue what could be causing my problems?

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kaefert (kaefert) said : 		#7

ähm.. not solved.. (see above)

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Launchpad Janitor (janitor) said : 		#8

This question was expired because it remained in the 'Open' state without activity for the last 15 days.