Extremely slow network

Boris Glawe public at boris-glawe.de
Tue Dec 16 20:51:42 UTC 2008


Hi,


My system:
Fedora 10 on an Athlon XP 2800+, with 3GB RAM and two onboard network 
adapters ("Marvell Technology Group Ltd. 88E8001 Gigabit Ethernet 
Controller" and "nvidia Corporation nForce2 Ethernet Controller"). My 
board is an Asus A7N8X-E Deluxe.

My problem is an extremely slow websurfing experience. Though I have an 
6Mbit/s DSL connection, surfing feels like with an 56KBit modem. There's 
almost no network traffic and almost no CPU usage shown in the (gnome) 
system monitor. The data transfer hangs sometimes in the state "looking 
up www.someURL.com" and sometime in the state "waiting for 
www.someURLcom". So it's possibly not primarily a DNS problem.

An other fact to mention is, that downloads are as fast as expected! 
Only the loading of normal webpages is very slow!

I've googled already and found some performance issues related with 
ipv6. Many postings/threads recommended to disable ipv6 dns lookups in 
firefox (about:config -> network.dns.disableIPv6;true), which did not help.

Others recommended to disable ipv6 completely:

Though all my interfaces have ipv6 disabled (IPV6INIT=no in 
/etc/sysconfig/networking-scripts/ifcfg-*  most of them have an inet6 
address (controlled with ifconfig). ip6tables is also disabled 
("chkconfig ip6tables off" and "service ip6tables stop")!

The next idea was to prevent the ipv6 module from being loaded into the 
kernel.
Though I added the line
"blacklist ipv6"
to /etc/modprobe.d/blacklist, the rebooted system had the ipv6 module 
loaded into the kernel. The only way to disallow the loading of the 
module was to add "install ipv6 /bin/true" to /etc/modprobe.conf

After a reboot I finally had a system with no ipv6 modules loaded and no 
inet6 addresses assigned to my network adapters.

BUT: Web surfing is still as slow like as in the early days of the internet.




So assume, that the enabled ipv6 protocol stack is not the reason for my 
problem. Do you agree?




I have two ethernet  interfaces in my machine.

One is connected with my dsl modem, the other is connected with my 
laptop (no switch, but a direct connection). My Laptop is still running 
a Fedora 9 installation.

I've configured my Fedora 10 Desktop to forward traffic between the 
interfaces and to apply NAT masquerading for packages that are routed 
from my laptop to the external DSL interface  (which is ppp0).

The amazing thing is: I do not have any performance issues with my 
laptop! The connection is smooth and perfectly fast. The DNS server (the 
same server, that's being used by my desktop) responds immediately and 
webpages are being loaded within a second or two.



I don't know what to do next!

Do you have any idea???


Thanks for any hints and ideas!

Greets Boris







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