Wired network drops out frequently in Fedora
 

Hi guys,
I'm having issues with my wired network. After about 5-10 minutes of turning on my machine, the network will drop out. Sometimes rebooting my pc or router will fix the connection, other times it will have no effect. Also, sometimes the connection will completely disconnect, other times it will appear to be connected (i.e. the network icon will indicate that there is a connection), but trying to ping a remote server or the router will fail.

This problem first showed up on Fedora 11 64, however I've just installed Fedora 13 64 and that hasn't helped. I'm using a brand new NIC (I've tried using the onboard NICs). The machine also has Windows 7 installed, which is able to connect just fine.

Apart from changing NICs, the only other thing I've tried is switching from dhcp to a static IP address.

Any tips or suggestions would be greatly appreciated.
Thanks

go back to dhcp. You can usually assign ips to mac addresses in the router, so you end up with a fixed ip.

Ive tried dhcp and static, neither of which has worked. Currenty I'm using dhcp. I've also tried disabling the firewall, which hasn't helped.

I've tried using my wireless dongle, which also hasn't worked. I'm albe to connect wirelessly for about 5-10 minutes but I'm still disconnected eventually. When I try to re-connect, I'm asked for the password (meaning that I can still the network), but am unable to hook up.

Does anyone have any suggestions or know of any doccuments that deal with these types of issues?

Thanks.

Does anyone have any ideas? I know bumping is looked down upon, but I'm really at a loss. Sometimes I'm able to maintain a connection for an hour, sometimes less than 5 minutes; there's no (obvious) cause for this sort of variance.

Use "iwconfig" and "route" to check the interface settings and the route settings. Read through the kernel messages for the period of time when the problem starts. Consider disabling ipv6. Try to ping the router from another computer on your lan if you have one. Look at the ethtool command to examine your devices settings and capabilities.

For my sins, I had to offer 'technical support' to people with video senders who were using the things to leach a second output from their pay tv boxes.

One of the first guys was doing everything right but nothing was working. After 15 minutes, I eventually discovered there was a wall blocking his signal and it was 2 feet thick!

Set up and sit beside the router for 20 minutes. Does it drop out?

Business kid: I lose my connection both wirelessly and wired. I've tried connecting using a 3m ethernet cable, used multiple cables and multiple NICs.

Jschiwal: I'm able to ping my router from other PCs on the network (one of which is an eeePC running Xandros Linux). I've also tried disabling IPV6. The system was unable to find the command ethtools.

Results for commands below:
Kernel Messages:
The full kernel messages are attached as kernel.txt

Thanks

Just looking at your kernel.txt there's a whole lot of weird stuff going on with the interrupts and pci bus. I'm on 2.6.33.2 and I don't have half that crap about pci bus & interrupts. The last 4 lines tell you why your connection is dropping
r8169: eth0: link down
r8169: eth0: link up
r8169: eth0: link down
r8169: eth0: link up

One possibility adding these 2 is that the hardware is dropping out in the box - and I would suspect your interrupt setup. You seem to have gone at everywhere else fairly effectively. You have eliminated everything except things shared by eth0 & wlan0. Can you try default safe settings in the bios? And if the interrupts are on 'edge' set them to 'level' and vice versa.

One other possibility is that the terms of connection from your router is not broadcast (like mine)
dhcpIPaddrLeaseTime=604800 in DHCP server response.
dhcpT1value is missing in DHCP server response. Assuming 302400 sec
dhcpT2value is missing in DHCP server response. Assuming 529200 sec

And somehow that's falling over. Does changing the default lease time in your router affect how regularly it falls over?

In my experience, 95% of link down errors are due to bad cables. But since you've not only tried different cables, but different NICs as well, this issue may be a little tougher to troubleshoot than normal. One thing you should try is manually setting the duplex on both ends (router and NIC), do not let the them auto-negotiate.

Also, if "r8169" stands for Realtek 8169 NIC, then you should consider switching NICs again. They are notorious for having link issues in linux. Just google it and you'll see what I mean.

Sorry for the delay in my reply, I've been away from home for a few days.

I've tried defaulting my BIOS without any luck. I'm not able to set the type of PCI interrupt. Below are my available PCI settings (current setting in bold)

Init Display First
-PCI Slot
-PCIEx

Reset Configuration Data
-Disabled
-Enabled

Resources Controlled By
-Auto(ESCD)
-Manual
(Changing to manual allows the option of assigning to PCI Device or Reserving IRQ 9, 10, 11, 14 and 15)

PCI/VGA Palette Snoop
-Disabled
-Enabled

PCI Latency Timer(CLK)
-32
-Any number between 0 and 255

...

My router does not have options for changing Duplex or Lease Time (I'm using a Netgear DGN2000, which is a combo ADSL Modem / Wireless Router). Below is my current status and settings:

WAN Setup
NAT:
-enabled
-Disabled
-No Firewall

PPPoE Relay:
-enabled
-Disabled

MTU Size
-1492

SIP ALG
-enabled
-Disabled

LAN Settings
IP Address:
-192.168.0.1

DHCP:
-On
-Off

Subnet Mask:
-255.255.255.0

RIP Direction:
-None
-In Only
-Out Only
-Both

RIP Version
-RIP-1
-RIP 2-B
-RIP 2-M

Use Router as DHCP Server
-Enabled
-Disabled

UPnP
-Enabled
-Disabled

...

Thanks

OK. So try this. Try it when you connect, and when you drop out

iwlist wlan0 scan |grep -e 'Quality' -e 'ESSID'

and check it. You may see a difference in your signal strength

For the r8169 device, you might try loading the kernel module with a debug option to get more information.
EG: "sudo /sbin/modprobe r8169 debug=8"

According to modinfo, "0=none,...,16=all"

The uPnP setting of your router might be dangerous. Even if it isn't the cause of the problem, setting it to no might be prudent.

Please, begin to do something on internet, then when link will go down, type on root console:
ifconfig eth0
ethtool eth0

Post outputs here without any private information.

After running iwlist a few times, there is no noticeable drop in signal quality when using the wireless dongle (signal strength hovers between 65-69 / 70).

Below are the outputs of iwconfig and ethtool

I'm currently using one of the onboard NICs, rather than the Realtek 8169. I'm also waiting on a friend to return my spare router. Once I've got that back I'll give it a try.