Upgrade to Hardy slows down internet

[Nomad]

I've updated to Hardy today, and it all works fine, except my internet connection.

It's painfully slow. Sometimes (usually) it doesn't work at all, sometimes it rises to ~30kbps, which is about a quarter of my connection. Wlassistant tells me that the wireless signal is at 5/5 stars, and it works normally on Windows too. That means Kubuntu is to blame

Although the wireless signal is at full strenght, the connection to the router via firefox is as slow as the rest of the net. I even disabled the firewall, but that didn't change anything.

However, when I shut down Kubuntu, it showed me a couple of pages full of messages (from dmesg) about received packets, which it didn't do before. I couldn't read them because they disappeared fast and the system shut down.

Can you suggest me something to fix this problem?

[dibl]

Re: Upgrade to Hardy slows down internet

Maybe disabling IPv6 in Firefox will fix it. I cannot recall the exact procedure -- search here, or probably just Google "disable ipv6 firefox" and get the detailed steps.

[Nomad]

Re: Upgrade to Hardy slows down internet

I disabled IPv6 globally (in /etc/modprobe.d/aliases), but it didn't fix the issue. The thing it, it all runs normally for some time, then stops suddenly.

I found this interesting message by dmesg:
There were several line like this one:

[ 123.041821] DROPPED IN= OUT=wlan1 SRC=192.168.2.101 DST=83.22.6.220 LEN=60 TOS=0x00 PREC=0x00 TTL=64 ID=57591 DF PROTO=TCP SPT=2996 DPT=7243 SEQ=2889931322 ACK=0 WINDOW=5840 RES=0x00 SYN URGP=0 OPT (020405B40402080AFFFF43990000000001030307)

, except with different DST addresses. 192.168.2.101 is the LAN address of my computer.
The last line is, however,

[ 974.091153] possible SYN flooding on port 6881. Sending cookies.

6881 is the ktorrent's port, and I figured that closing ktorrent makes my net work. However, I still feel it's a little to slow (30kB/s instead of 100+).