periodically interrupted Internet

English Network/Internet
#1

From version 11.3 to 11.4 now often occurs after a problem has already become annoying! My computer connects to intertet through a router and sometimes after about 4, 5 hours going through the browser so I can not reach Google or someone else’s server Skype only stays connected!
This is not a hardware problem occurs because even after changing the router and the computer problem remains!
When this happens the router has access to the Internet and other computer via wifi can connect without a problem!
Please for ideas on how to figure out where the problem comes?
I attach the output of dmesg:

[40285.897112] SFW2-INext-ACC-TCP IN=eth0 OUT= MAC=1c:6f:65:81:21:73:00:1e:65:90:c9:a6:08:00 SRC=192.168.1.102 DST=192.168.1.100 LEN=60 TOS=0x00 PREC=0x00 TTL=64 ID=57753 DF PROTO=TCP SPT=44432 DPT=22 WINDOW=4380 RES=0x00 SYN URGP=0 OPT (020405B40402080A001F96780000000001030307)

I checked this code in google and found that a similar prolem had people from the version 10.3 but I do not remember then I had this problem occur examples of 11,3

Please for ideas on how to figure out where the problem comes?

#2

The code You posted is irrelevant. It is some firewall log entry I believe (it’s almost impossible for firewall rules to change over time by themselves).

If Skype works than it looks like a DNS problem because Skype does not need DNS to work.
Next time, when You get the disruption please try to ping 8.8.4.4 (public google DNS server) and post the output of :

cat /etc/resolv.conf

It also might be that You have ipv6 enabled and something among the way does not handle ipv6 DNS requests properly. Disabling ipv6 might solve the problem or have no effect at all if the problem lies somwhere esle.

Best regards,
Greg

#3

Thanks for the reply, I think you are right about everything!

#4

I sure hope so :slight_smile: lets just wait and see.

Best regards,
Greg

#5

Unfortunately the problem is not just in this…!

I changed the router DNS to OpenDNS 208.67.222.222 and 208.67.220.220 also waved IPv6! After nine hours running smoothly, it appears the problem!
I followed> ping 208.67.222.222 - had a connection
cat / etc / resolv.conf shows these IP addresses

Now switched to google dns 8.8.4.4

#6

I’m afraid the switch won’t do any good. The problem might be something else I’m afraid but I have a few more questions to ask.

How did You disable ipv6 ?
What is the contents of this file on your system ?

/etc/sysctl.conf

Did You disable ipv6 in your internet browser ?

Are You able to ping something by it’s DNS name when this happens ? Here’s an example output :

~> ping lwn.net
PING lwn.net (72.51.34.34) 56(84) bytes of data.
64 bytes from sb.lwn.net (72.51.34.34): icmp_req=1 ttl=49 time=191 ms
64 bytes from sb.lwn.net (72.51.34.34): icmp_req=2 ttl=49 time=190 ms
64 bytes from sb.lwn.net (72.51.34.34): icmp_req=3 ttl=49 time=187 ms
^C
--- lwn.net ping statistics ---
3 packets transmitted, 3 received, 0% packet loss, time 2001ms
rtt min/avg/max/mdev = 187.189/189.692/191.718/1.879 ms

Best regards,
Greg

#7

I disable ipv6 using yast>network settings,mozilla IPv6 disable using about:config.

/etc/sysctl.conf

niki@box:~> sudo cat /etc/sysctl.conf

Disable response to broadcasts.

You don’t want yourself becoming a Smurf amplifier.

net.ipv4.icmp_echo_ignore_broadcasts = 1

enable route verification on all interfaces

net.ipv4.conf.all.rp_filter = 1

disable IPv6 completely

net.ipv6.conf.all.disable_ipv6 = 1

enable IPv6 forwarding

#net.ipv6.conf.all.forwarding = 1

increase the number of possible inotify(7) watches

fs.inotify.max_user_watches = 65536

avoid deleting secondary IPs on deleting the primary IP

net.ipv4.conf.default.promote_secondaries = 1
net.ipv4.conf.all.promote_secondaries = 1

When this happens
I ping zamunda.net and it`s ok!

#8

Looks like You have disabled ipv6 cprrectly.

What does this mean ? You get a disruption in access to google.com and all the other sites except zamunda.net ?

Best regards,
Greg

#9

What does this mean ? You get a disruption in access to google.com and all the other sites except zamunda.net ?

No, i ping google too ! Browser only ,and vlc connection whit video streaming site not working !I think ktorrent has something to do with what happens.
Because lately does not work properly. Once the torrent is deleted is displayed again and so several times. Today I noticed that maybe has something to do

#10

Ok I think I had the same problem. Had to disable ktorrent using the μTP protocol. When I get home I can give You a screenshot of the setting but I’m sure You will find the setting yourself.

Best regards,
Greg

#11

Ok I think I had the same problem. Had to disable ktorrent using the μTP protocol. When I get home I can give You a screenshot of the setting but I’m sure You will find the setting yourself.

I disable uTP protocol but this not fix the problem!

#12

Ok than I’ve got no idea what the problem is :slight_smile: I think your best bet is to submit a bug report in the bugzilla.

Best regards,
Greg

#13

Look what I found:

cat /var/log/messages
Jun 28 07:52:55 box pppd[2877]: Interface eth0 has MTU of 576 – should be at least 1500.
Jun 28 07:52:55 box pppd[2877]: This may cause serious connection problems.

niki@box:~> sudo /sbin/ifconfig -a
root’s password:
eth0 Link encap:Ethernet HWaddr 1C:6F:65:81:21:73
inet addr:192.168.1.100 Bcast:255.255.255.255 Mask:255.255.255.0
UP BROADCAST RUNNING MULTICAST MTU:576 Metric:1
RX packets:3522697 errors:0 dropped:3 overruns:0 frame:0
TX packets:6154209 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000

      RX bytes:1328024379 (1266.5 Mb)  TX bytes:2762052255 (2634.0 Mb)
      Interrupt:40 Base address:0xe000

lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.0.0.0
UP LOOPBACK RUNNING MTU:16436 Metric:1
RX packets:1521 errors:0 dropped:0 overruns:0 frame:0
TX packets:1521 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:75628 (73.8 Kb) TX bytes:75628 (73.8 Kb)

Consider the following links
fedora - network bridge default MTU – apparent change
https://bugzilla.redhat.com/show_bug.cgi?id=574629
[ubuntu] Default MTU setting changed from 1500 to 576 upgrading to 8.10; this is bad! - Ubuntu Forums](http://ubuntuforums.org/showthread.php?t=972612)

#14

Please use code tags when posting command line output in the future :slight_smile:
Posting in Code Tags - A Guide

Such small frame size can indeed cause problems. Are You using NetworkManager or ifup ?

If using ifup how does the following file look like ?

cat /etc/sysconfig/network/ifcfg-eth0

Best regards,
Greg

](http://forums.opensuse.org/english/get-technical-help-here/how-faq-forums/advanced-how-faq-read-only/451526-posting-code-tags-guide.html)

#15

Thank you for helping me,Greg!

niki@box:~> cat /etc/sysconfig/network/ifcfg-eth0
BOOTPROTO='dhcp4'
BROADCAST=''
ETHTOOL_OPTIONS=''
IPADDR=''
MTU=''
NAME='RTL8111/8168B PCI Express Gigabit Ethernet controller'
NETMASK=''
NETWORK=''
REMOTE_IPADDR=''
STARTMODE='nfsroot'
USERCONTROL='yes'
#16

You’re welcome. Hopefully we will get to the bottom of this :slight_smile:

Looks good. Try to change MTU=’’ to MTU=‘1500’ in order to force the value. Use ifconfig to see if that helps. Btw You can use ifconfig with your standard user privileges in order to just see the results.

Best regards,
Greg

#17

I think this time we found the reason for the interruption. But I’m curious why did this happen,why it is necessary to fix MTU setting.
What sets the MTU value to 576 before I fix it?

#18

Maybe pppd does that. I’m not sure. Are You using some dial up connection to get to the internet ?

Best regards,
Greg