How can it be, that sometimes I can not browse almost the whole Internet
but very few sites like google or bloomberg. apt-get install doesn't
work either. At the same time amule and ktorrent work fine, I can log
into remote computers with telnet or ssh. This takes place both when
Kubuntu 7.10 or Fedora Core 6 are loaded. However when reloaded into Windows XP everything is fine.

I have this problem not permanently. Perhaps my internet provider time after time reloads his server with or without some firewalls or somthing else and I can't browse html pages.

In those days when there is a problem the command
ifonfig -a indicates RX packets errors:

eth0 Link encap:Ethernet HWaddr 00:13:8F:37:71:AF
inet addr:84.15.65.28 Bcast:84.15.65.63 Mask:255.255.255.192
inet6 addr: fe80::213:8fff:fe37:71af/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:2722 errors:94 dropped:0 overruns:0 frame:94
TX packets:954 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:869190 (848.8 KB) TX bytes:255064 (249.0 KB)
Interrupt:19 Base address:0xdead

lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.0.0.0
inet6 addr: ::1/128 Scope:Host
UP LOOPBACK RUNNING MTU:16436 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:0 (0.0 b) TX bytes:0 (0.0 b)

My box has ASRock 939S56-M Motherboard with AMD64 processor and
Silicon Integrated 190 Gigabit Ethernet Adapter

You might have more than one problem here. It is apparent from the (Linux) ifconfig report that your Ethernet link is having problems. Your post doesn't say what the Ethernet port is connected to, but if it is connected to a router or other device that actually supports 1Gb signalling rate, you might have a bum cable. (Cat 5 is probably not good enough; Cat 5e might be, if the distance is short and the cable carefully made; Cat 6 ought to be OK.)

It would be instructive to find out if Windows is seeing the same sorts of errors, but coping with them better. To see this info, get a command window open while Windows is running (and there seems to be a problem), and give the command This will produce a report sort of like the one that Linux ifconfig produces.

If you see the same fraction of errors, but not the misbehavior, I would look very closely at whether the Ethernet driver you have installed in the Linux box actually supports your hardware. If not, find one that does.

HTH

Unfortunately today I can browse within Linux, and ifconfig -a reports no errors, so there is no sense to check Windows netstat -e report. Shall wait
until the next time. Usually it happens on the weekends when I am switched from the erroneous to the correct network functioning or vice versa.Perhaps admins of my ISP have a habitude to reload their servers in these days.

Yet theoretically I don't understand what the Google or Bloomberg sites have to do with my supposedly bum cable. Why can I browse these two sites during the time when ifconfig -a reports errors?

I still suspect that some ports are closed for me when I have reception erros. How should I check these ports?

Or it is the driver that I should suspect?
Here I have one more note about the driver. In 2004 I had a similar but exactly the opposite problem. At the workplace I was very proud of being first to use Linux except that I had to be silent about not being able to browse Google. Although almost all other sites were opened finely. It was Red Hat 9 with the erroneus driver for 3Com 10/100 PCI ethernet card on Asus P4P800 motherboard. Only after installation of FC2 the problem was fixed. There are still few posts about this problem:

http://www.linuxquestions.org/questi...s-fine.-87439/
http://www.linuxquestions.org/questi...sus+p4p800+rh9

So, it doesn't work again today:

ifonfig -a gives
eth0 Link encap:Ethernet HWaddr 00:13:8F:37:71:AF
inet addr:84.15.65.28 Bcast:84.15.65.63 Mask:255.255.255.192
inet6 addr: fe80::213:8fff:fe37:71af/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:8220 errors:240 dropped:0 overruns:0 frame:240
TX packets:438 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:580838 (567.2 KB) TX bytes:49191 (48.0 KB)
Interrupt:19 Base address:0xdead


And meantime windows shows no errors:

Microsoft Windows XP [Version 5.1.2600]
C:\Documents and Settings\Erne>netstat -e
Interface Statistics
Received Sent

Bytes 946405 204855
Unicast packets 2590 2396
Non-unicast packets 913 39
Discards 0 0
Errors 0 0
Unknown protocols 0

My further research indicates that this is very likely a bug that is being worked on. Your initial post said that you have a SiS 190 Ethernet interface; this thread details work that is going on with the driver to fix problems that look a lot like yours: http://bugzilla.kernel.org/show_bug.cgi?id=9386

Until this debugging work is done, I think there is not a lot that you can do at your end (unless you have another maker's Ethernet card handy). Eventually, you will probably want to upgrade the kernel.