strange problem: only some website works

[atariworld]

I have installed on my new laptop (Asus 64 bit dual core 2) a Fedora Core 6.
I'm having a strange problem:

- with both Firefox and Konqueror I can only access to Google and few other websites. I can't load most of the websites (the behaviour is as if the servers were down)
- I'm not able to access the router configuration address: 192.168.1.1
- on the terminal everything seems ok (ping and traceroute works)
-trying the same PC on another network everything works fine
- I tried to reinstall FC6 resetting all the system and disabling (during the installation) SELinux, Firewall and ipv6
- I tried to insert OpenDNS addresses but the problem still remains
- I tried to insert in the browser address'bar the IPs instead of the names and nothing changed (the behaviour was the same: most of the website weren't loaded even inserting their ip address instead of the name)
- Windows XP on the same computer and OSX on another computer work fine
- the last version of SUSE linux 64 bits gave me the same problem

What could it be ?
Why with windows and osx everything works fine but these new version of linux are giving me this problem ?

Thankyou very much

[erroneus]

Sounds like you have network config problems. Show us some "route -n" and "ifconfig" output.

[atariworld]

[root@localhost ~]# ifconfig
eth0 Link encap:Ethernet HWaddr 00:18:F3:65:FA:65
inet addr:192.168.1.6 Bcast:192.168.1.255 Mask:255.255.255.0
inet6 addr: fe80::218:f3ff:fe65:fa65/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:24 errors:0 dropped:0 overruns:0 frame:0
TX packets:57 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:2633 (2.5 KiB) TX bytes:8391 (8.1 KiB)
Interrupt:185 Base address:0x8c00

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:1334 errors:0 dropped:0 overruns:0 frame:0
TX packets:1334 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:2141440 (2.0 MiB) TX bytes:2141440 (2.0 MiB)

[root@localhost ~]# route -n
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
192.168.1.0 0.0.0.0 255.255.255.0 U 0 0 0 eth0
169.254.0.0 0.0.0.0 255.255.0.0 U 0 0 0 eth0
0.0.0.0 192.168.1.1 0.0.0.0 UG 0 0 0 eth0
[root@localhost ~]#

Thankyou
P.S. I have just tested a live DVD of Ubuntu 6.06 and it works fine. So it is only Fedora core 6 and OpenSuse that have something to complain with my router.

[erroneus]

and "cat /etc/resolv.conf"?

The output you provided looks pretty normal... it's rather puzzling.

[sej7278]

this looks like the old problem with "window size" or something, i can't quite remember what it was - it's essentially a setting that got put into the kernel around fc5 that makes it less forgiving of crappy routers, i had it with the adsl router from tiscali, but my freebox and netgear work fine.

you could also try putting the mtu on your router down to 1400, this helps with relaxx and aol connections.

i really don't think it's anything to do with your fedora.

[atariworld]

[atari@localhost ~]$ cat /etc/resolv.conf
; generated by /sbin/dhclient-script
nameserver 192.168.1.1
search localdomain
[atari@localhost]

Thankyou,

[erroneus]

I have to concur with the suggestion from sej7278:

It has been a REALLY long time since I have seen it, but the packet size thing rings a bell. Play with the MTU size on the router (if there is such a setting) and with the computer's settings too.

[atariworld]

I agree with you that probably the problem is in some window/packet size...
I tried to bring the MTU in Fedora from 1492 to 1500 but it this hasn't solved the problem completely (i.e. some websites are still unreachable)...

Now I installed Ubuntu that works fine. I will probably install again Fedora next year when I will change my ISP and router.

Thankyou for your help

[jcliburn]

The problem was almost certainly related to TCP window scaling. Next time you run into the problem, try this as root and see if it fixes your stalled connections.

echo 0 > /proc/sys/net/ipv4/tcp_window_scaling

By the way, it's related to the kernel version you run, not to the distribution you choose (unless that distro turns off TCP window scaling by default).