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Old 09-30-2007, 11:29 AM   #1
sina_kish
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Registered: Jan 2005
Location: Sweden
Distribution: SuSE
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Strange Errors in Received Packets on an Ethernet connection


Hello Everybody,

I have recently moved to my new home and here my Internet connection is a broadband and I use Ethernet cable to connect to my ISP.

I have a very annoying problem though. around 60% of times when I connect to the Internet, I have a very slow connection. I do ifconfig eth1 and here is the output: (I'm running SuSE 10.2)

eth1 Link encap:Ethernet HWaddr 00:c3:6c:7b:80:7f
inet addr:213.x.x.x Bcast:213.x.x.x Mask:255.255.255.192
UP BROADCAST NOTRAILERS RUNNING MULTICAST MTU:1500 Metric:1
RX packets:4900 errors:990 dropped:0 overruns:0 frame:0
TX packets:4173 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:4060839 (3.8 Mb) TX bytes:667364 (651.7 Kb)
Interrupt:217 Base address:0x2400


As you can see, I have errors in received packets. dmesg also shows something like this:

SFW2-INext-DROP-DEFLT IN=eth1 OUT= MAC=01:00:5e:00:00:01:00:04:28:f2:60:00:08:00 SRC=213.x.x.x DST=224.0.0.1 LEN=28 TOS=0x00 PREC=0xC0 TTL=1 ID=63125 PROTO=2

I have disabled IPV6 in firefox and konqueror and in modprobe.conf, but it keeps being like this. Sometimes when I restart the system everything is fine.

Also at some point I thought maybe the problem is caused by duplex mismatch, but my ISP says we always run on 10Mbps half duplex and ethtool shows the same settings on my network card settings.

I'm really confused and don't know what might be the problem. Any help or suggestion is highly appreciated. The point is I don't have such problems in my office or other places, so I don't think I have a hardware problem.

/Sina
 
Old 09-30-2007, 08:08 PM   #2
jcliburn
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What kernel version (uname -r), what NIC (lspci -nn | grep -i eth)?

You might try changing the MTU size to 1400. If it helps, gradually work back up toward 1500 and find the point at which you begin to see errors.

I'm intrigued by this line of your ifconfig output:

Interrupt:217 Base address:0x2400

Could you please post the output of this command:

cat /proc/interrupts
 
Old 10-02-2007, 04:49 PM   #3
sina_kish
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Quote:
Originally Posted by jcliburn View Post
What kernel version (uname -r), what NIC (lspci -nn | grep -i eth)?

You might try changing the MTU size to 1400. If it helps, gradually work back up toward 1500 and find the point at which you begin to see errors.

I'm intrigued by this line of your ifconfig output:

Interrupt:217 Base address:0x2400

Could you please post the output of this command:

cat /proc/interrupts


I'm using this kernel : 2.6.18.2-34-default

lspci command with -nn switch does not print out anything, but this is the output of lspci without -nn:

06:07.0 Ethernet controller: Realtek Semiconductor Co., Ltd. RTL-8139/8139C/8139C+ (rev 10)

and here is cat /proc/interrupts:

CPU0
0: 5328224 IO-APIC-edge timer
1: 11077 IO-APIC-edge i8042
8: 2 IO-APIC-edge rtc
9: 193412 IO-APIC-level acpi
12: 789659 IO-APIC-edge i8042
14: 201372 IO-APIC-edge ide0
50: 0 IO-APIC-level ehci_hcd:usb1, uhci_hcd:usb2
58: 1 IO-APIC-level ohci1394
169: 1266944 IO-APIC-level uhci_hcd:usb5, fglrx
177: 764309 IO-APIC-level Intel ICH6
185: 1 IO-APIC-level yenta, sdhci:slot0, sdhci:slot1, sdhci:slot2
217: 1189363 IO-APIC-level ipw2200, eth1
225: 0 IO-APIC-level uhci_hcd:usb4
233: 0 IO-APIC-level uhci_hcd:usb3
NMI: 0
LOC: 5328132
ERR: 0
MIS: 0

One interesting thing that I have discovered by accident, though I'm not 100% sure if it is always true, is that, as I have a dual boot windoz/linux machine, when I boot to windows my connection is usually fine. And then when I reboot back to Linux, the connection becomes without those error packets. Do you think there are some hardware registers or bios settings that are being manipulated by windows?

Thanks
/S
 
Old 10-02-2007, 07:14 PM   #4
jcliburn
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I presume this is a laptop? If so, ignore #3 below.

None of this may help, but:

1. Try changing the MTU size. ifconfig eth1 mtu 1400

2. Try booting with noirqbalance on your kernel command line.

3. If the NIC isn't an onboard chip, try a different PCI slot. Looks like your wireless device and your wired NIC are sharing an interrupt line.

It would be a good idea to capture NIC stats when it's performing well and compare those results against a similar capture when the NIC is misbehaving. An easy way to capture stats is

ethtool -S eth1

By the way, that iptables drop in your syslog appears to be a broadcast packet from some other host on your LAN (with a thoroughly weird mac address).
 
Old 10-04-2007, 12:25 PM   #5
sina_kish
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Yes, This is a laptop.

I tried to change the mtu to 1400 and up but it didn't have any effects.

here is the output of ethtool -S eth1 in both good and bad network connection. unfortunately my NIC driver does not provide more detailed information:

ethtool -S eth1
NIC statistics:
early_rx: 0
tx_buf_mapped: 0
tx_timeouts: 0
rx_lost_in_ring: 0


But one thing that I'm now pretty sure because I purposefully tested it, is the following:

When I turn on the laptop and I boot into Linux and the connection contains error packets, I reboot to windows and usually it is also very slow. Then I simply disconnect and reconnect the cable to laptop ethernet tool, and after a few seconds the message "limited or no connectivity" is displayed and then suddenly the message "connected" pops up and the speed is very good this time! Then I immediately reboot to Linux and I don't have a single error packet!!

I'm pretty sure there are some auto negotiation stuff going on in between the switch and my computer and they are saved somewhere in a register or so. And then Linux uses those saved configurations.

I have tried to reboot Linux multiple times when this problem occurs, and it will remain with error packets until I perform the above mentioned procedure. So windows is doing some magic for me.

I'm totally perplexed now.

By the way, aren't those strange mac addresses an ipv6 related stuff?
 
Old 10-04-2007, 07:31 PM   #6
jcliburn
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Quote:
Originally Posted by sina_kish View Post
I have tried to reboot Linux multiple times when this problem occurs, and it will remain with error packets until I perform the above mentioned procedure. So windows is doing some magic for me.
I guess at this point I'd try and figure out whether or not the switch is the source of the problem. Can you remove it from the path and see if your problem persists?

Quote:
By the way, aren't those strange mac addresses an ipv6 related stuff?
No, mac addresses are the same irrespective of whether the message is IPv4 or v6. You can see the source and destination addresses (SRC, DST) in your log entry are ipv4 addresses; it's a v4 IGMP message (proto=2), probably your router broadcasting for group members.
 
  


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