[LARTC] Random ping jumps

[LARTC] Random ping jumps

[Artūras Šlajus]

Hello,

   I've got this problem. There is an linux server with 2.4.24 kernel
and pinging from him to internet (or from lan) ping randomly jumps up:

64 bytes from fortas.ktu.lt (193.219.160.131): icmp_seq87 ttlY time0.0 ms
64 bytes from fortas.ktu.lt (193.219.160.131): icmp_seq88 ttlY time2.6 ms
64 bytes from fortas.ktu.lt (193.219.160.131): icmp_seq89 ttlY time4.9 ms
64 bytes from fortas.ktu.lt (193.219.160.131): icmp_seq90 ttlY time\x198 ms
64 bytes from fortas.ktu.lt (193.219.160.131): icmp_seq91 ttlY time@7 ms
64 bytes from fortas.ktu.lt (193.219.160.131): icmp_seq92 ttlY time@7 ms
64 bytes from fortas.ktu.lt (193.219.160.131): icmp_seq93 ttlY timeC0 ms
64 bytes from fortas.ktu.lt (193.219.160.131): icmp_seq94 ttlY time0.9 ms
64 bytes from fortas.ktu.lt (193.219.160.131): icmp_seq95 ttlY time1.6 ms

   Internet line isn't loaded up, server load fine. QOS isn't used, qdiscs default.
I don't realize what the problem is and even how to debug it. Sysctl config:
net/ipv4/ip_forward = 1
net/ipv4/icmp_ignore_bogus_error_responses = 1
net/ipv4/icmp_echo_ignore_broadcasts = 1
net/ipv4/tcp_syncookies = 1
net/ipv4/tcp_timestamps = 0
net/ipv4/tcp_window_scaling = 0
net/ipv4/tcp_sack = 0
net/ipv4/tcp_fin_timeout = 30
net/ipv4/tcp_keepalive_time = 1800
net/ipv4/tcp_low_latency = 1

Thanks for any thoughts.


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Re: [LARTC] Random ping jumps

[Roy]

I think it is your privider fault, Isnt your provider litnet? and you
connected with some wlan card

to debug it trace the patch (with traceroute or tracert) and try to ping the
most near routers, this way you will easy find the problem




> Hello,
>
>    I've got this problem. There is an linux server with 2.4.24 kernel
> and pinging from him to internet (or from lan) ping randomly jumps up:
>
> 64 bytes from fortas.ktu.lt (193.219.160.131): icmp_seq87 ttlY
time0.0 ms
> 64 bytes from fortas.ktu.lt (193.219.160.131): icmp_seq88 ttlY
time2.6 ms
> 64 bytes from fortas.ktu.lt (193.219.160.131): icmp_seq89 ttlY
time4.9 ms
> 64 bytes from fortas.ktu.lt (193.219.160.131): icmp_seq90 ttlY
time\x198 ms
> 64 bytes from fortas.ktu.lt (193.219.160.131): icmp_seq91 ttlY
time@7 ms
> 64 bytes from fortas.ktu.lt (193.219.160.131): icmp_seq92 ttlY
time@7 ms
> 64 bytes from fortas.ktu.lt (193.219.160.131): icmp_seq93 ttlY
timeC0 ms

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Re: [LARTC] Random ping jumps

[Artūras Šlajus]

Roy wrote:

> I think it is your privider fault, Isnt your provider litnet? and you
> connected with some wlan card
no. my provider is Lithuania telecom. And i'm on DSL 320/128.

> to debug it trace the patch (with traceroute or tracert) and try to ping the
> most near routers, this way you will easy find the problem
i'll try using mrt.


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Re: [LARTC] Random ping jumps

[R. Steve McKown]

Can you provide some more detail on your network configuration?  I'm unclear 
if the linux server is your internet router or just another client computer 
on your local LAN, where the test pings to "the internet" are going (i.e. 
nexthop router, etc.), and if/where CIPE tunnels are involved in the 
equation.  Perhaps a small network map would be helpful.

I'm also unclear about the pings that you've tried.  After you've shown the 
network map, perhaps you can identify the two machines (and interfaces) 
involved in each of the different ping tests you've performed.

I had a similar problem recently.  A linux-based router with four interfaces 
serving three local LANs and a T-1 (via the provider's router) to the 
internet.  The router was forwarding traffic between all combinations of 
networks (that were allowed by rule) correctly, except between LANs 1 and 2.  
In this case, pings would vary much as in your case.  Interestingly, it 
turned out to be bad hardware.  Moved the boot media to an identically 
configured machine and the problem went away.  Returned the boot media to the 
original machine and the problem returned.

On Wednesday 07 January 2004 02:26 pm, Artūras Šlajus wrote:
> Hello,
>
>    I've got this problem. There is an linux server with 2.4.24 kernel
> and pinging from him to internet (or from lan) ping randomly jumps up:
>
> 64 bytes from fortas.ktu.lt (193.219.160.131): icmp_seq87 ttlY
> time0.0 ms 64 bytes from fortas.ktu.lt (193.219.160.131): icmp_seq88
> ttlY time2.6 ms 64 bytes from fortas.ktu.lt (193.219.160.131):
> icmp_seq89 ttlY time4.9 ms 64 bytes from fortas.ktu.lt
> (193.219.160.131): icmp_seq90 ttlY time\x198 ms 64 bytes from
> fortas.ktu.lt (193.219.160.131): icmp_seq91 ttlY time@7 ms 64 bytes
> from fortas.ktu.lt (193.219.160.131): icmp_seq92 ttlY time@7 ms 64
> bytes from fortas.ktu.lt (193.219.160.131): icmp_seq93 ttlY timeC0 ms
> 64 bytes from fortas.ktu.lt (193.219.160.131): icmp_seq94 ttlY
> time0.9 ms 64 bytes from fortas.ktu.lt (193.219.160.131): icmp_seq95
> ttlY time1.6 ms
>
>    Internet line isn't loaded up, server load fine. QOS isn't used, qdiscs
> default. I don't realize what the problem is and even how to debug it.
> Sysctl config: net/ipv4/ip_forward = 1
> net/ipv4/icmp_ignore_bogus_error_responses = 1
> net/ipv4/icmp_echo_ignore_broadcasts = 1
> net/ipv4/tcp_syncookies = 1
> net/ipv4/tcp_timestamps = 0
> net/ipv4/tcp_window_scaling = 0
> net/ipv4/tcp_sack = 0
> net/ipv4/tcp_fin_timeout = 30
> net/ipv4/tcp_keepalive_time = 1800
> net/ipv4/tcp_low_latency = 1
>
> Thanks for any thoughts.
>
>
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> http://mailman.ds9a.nl/mailman/listinfo/lartc HOWTO: http://lartc.org/

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Re: [LARTC] Random ping jumps

[Artūras Šlajus]

R. Steve McKown wrote:

> Can you provide some more detail on your network configuration?  I'm unclear 
> if the linux server is your internet router or just another client computer 
> on your local LAN
It's network router.

> , where the test pings to "the internet" are going (i.e. 
> nexthop router, etc.), and if/where CIPE tunnels are involved in the 
> equation.  Perhaps a small network map would be helpful.
No CIPE (whatever is that ;-). Nexthop? You mean gateway?
eth0:1    Link encap:Ethernet  HWaddr 00:50:22:B1:67:6D
            inet addr:81.7.84.36  Bcast:81.255.255.255  Mask:255.0.0.0
            UP BROADCAST RUNNING MULTICAST  MTU:1492  Metric:1
            Interrupt:10 Base address:0xd000
gateway: 81.7.84.1

Map is at http://h2o.pieva.net/net.png

> I'm also unclear about the pings that you've tried.  After you've shown the 
> network map, perhaps you can identify the two machines (and interfaces) 
> involved in each of the different ping tests you've performed.
The machine is totaly random.
x11@rasnet:~$ traceroute fortas.ktu.lt
traceroute to fortas.ktu.lt (193.219.160.131), 30 hops max, 38 byte packets
   1  adsl-213-190-40-129.takas.lt (213.190.40.129)  26.269 ms  23.333 ms  25.156 ms
   2  fe22-acc0-tai.kns.telecom.lt (212.59.7.233)  63.079 ms  33.146 ms  26.117 ms
   3  telecom-gw.is.lt (193.219.13.99)  35.978 ms  26.476 ms  103.138 ms
   4  litnet-gw.is.lt (193.219.13.98)  22.715 ms  24.531 ms  209.984 ms
   5  cat6506-p2-1.kttc.litnet.lt (193.219.62.125)  52.826 ms  98.040 ms  81.609 ms
   6  ktu-lan.litnet.lt (193.219.61.252)  38.696 ms  182.582 ms  241.836 ms
   7  fortas.ktu.lt (193.219.160.131)  215.523 ms  126.815 ms  29.217 ms

x11@rasnet:~$ traceroute cs.mes.lt
traceroute to cs.mes.lt (193.219.67.253), 30 hops max, 38 byte packets
   1  adsl-213-190-40-129.takas.lt (213.190.40.129)  748.174 ms  66.331 ms  135.586 ms
   2  fe22-acc0-tai.kns.telecom.lt (212.59.7.233)  21.645 ms  21.588 ms  24.597 ms
   3  telecom-gw.is.lt (193.219.13.99)  30.584 ms  31.065 ms  29.612 ms
   4  litnet-gw.is.lt (193.219.13.98)  24.602 ms  143.212 ms  143.096 ms
   5  cat6506-p2-1.kttc.litnet.lt (193.219.62.125)  292.196 ms  163.870 ms  84.549 ms
   6  ktu-lan.litnet.lt (193.219.61.252)  84.982 ms  54.801 ms  69.143 ms
   7  diz.ktu.lt (193.219.67.253)  33.831 ms  29.877 ms  30.005 ms
64 bytes from diz.ktu.lt (193.219.67.253): icmp_seq=5 ttlY time4.8 ms
64 bytes from diz.ktu.lt (193.219.67.253): icmp_seq=6 ttlY time2.6 ms
64 bytes from diz.ktu.lt (193.219.67.253): icmp_seq=7 ttlY time3.1 ms
64 bytes from diz.ktu.lt (193.219.67.253): icmp_seq=8 ttlY time24 ms
64 bytes from diz.ktu.lt (193.219.67.253): icmp_seq=9 ttlY timeƒ6 ms
64 bytes from diz.ktu.lt (193.219.67.253): icmp_seq\x10 ttlY time…0 ms
64 bytes from diz.ktu.lt (193.219.67.253): icmp_seq\x11 ttlY time21 ms
64 bytes from diz.ktu.lt (193.219.67.253): icmp_seq\x12 ttlY time\x147 ms
64 bytes from diz.ktu.lt (193.219.67.253): icmp_seq\x13 ttlY time\x115 ms
64 bytes from diz.ktu.lt (193.219.67.253): icmp_seq\x14 ttlY time\x118 ms
64 bytes from diz.ktu.lt (193.219.67.253): icmp_seq\x15 ttlY time\x107 ms
64 bytes from diz.ktu.lt (193.219.67.253): icmp_seq\x16 ttlY time\x107 ms
64 bytes from diz.ktu.lt (193.219.67.253): icmp_seq\x17 ttlY time'2 ms
64 bytes from diz.ktu.lt (193.219.67.253): icmp_seq\x18 ttlY time12 ms
64 bytes from diz.ktu.lt (193.219.67.253): icmp_seq\x19 ttlY time\x102 ms
64 bytes from diz.ktu.lt (193.219.67.253): icmp_seq  ttlY time\x107 ms
64 bytes from diz.ktu.lt (193.219.67.253): icmp_seq! ttlY time\x114 ms
64 bytes from diz.ktu.lt (193.219.67.253): icmp_seq" ttlY time‰.8 ms
64 bytes from diz.ktu.lt (193.219.67.253): icmp_seq# ttlY time‘.2 ms

x11@rasnet:~$ traceroute cs.bbd.lt
traceroute to cs.bbd.lt (193.219.184.7), 30 hops max, 38 byte packets
   1  adsl-213-190-40-129.takas.lt (213.190.40.129)  23.803 ms  24.813 ms  56.163 ms
   2  fe22-acc0-tai.kns.telecom.lt (212.59.7.233)  171.425 ms  21.174 ms  24.321 ms
   3  telecom-gw.is.lt (193.219.13.99)  27.882 ms  30.782 ms  26.219 ms
   4  litnet-gw.is.lt (193.219.13.98)  22.842 ms  23.025 ms  24.079 ms
   5  cat6506-p2-1.kttc.litnet.lt (193.219.62.125)  24.201 ms  25.130 ms  27.256 ms
   6  ktu-lan.litnet.lt (193.219.61.252)  26.811 ms  27.362 ms  27.785 ms
   7  193.219.184.7 (193.219.184.7)  27.928 ms  29.185 ms  28.067 ms
x11@rasnet:~$ ping cs.bbd.lt
PING cs.bbd.lt (193.219.184.7) 56(84) bytes of data.
64 bytes from 193.219.184.7: icmp_seq=1 ttl\x123 time\x133 ms
64 bytes from 193.219.184.7: icmp_seq=2 ttl\x123 time\x122 ms
64 bytes from 193.219.184.7: icmp_seq=3 ttl\x123 time\x118 ms
64 bytes from 193.219.184.7: icmp_seq=4 ttl\x123 time\x109 ms
64 bytes from 193.219.184.7: icmp_seq=5 ttl\x123 timer5 ms
64 bytes from 193.219.184.7: icmp_seq=6 ttl\x123 timef8 ms
64 bytes from 193.219.184.7: icmp_seq=7 ttl\x123 time\x120 ms
64 bytes from 193.219.184.7: icmp_seq=8 ttl\x123 time\x102 ms
64 bytes from 193.219.184.7: icmp_seq=9 ttl\x123 time‘.5 ms
64 bytes from 193.219.184.7: icmp_seq\x10 ttl\x123 time‘.7 ms

> I had a similar problem recently.  Interestingly, it 
> turned out to be bad hardware.
Another person told me that bad hw could be reason. But it works for
LAN perfectly.

  >  Moved the boot media to an identically
> configured machine and the problem went away.  Returned the boot media to the 
> original machine and the problem returned.
Sad, but i can't do that :(

My /etc/network/interfaces:
auto eth0
iface eth0 inet static
          address 192.168.0.1
          netmask 255.255.255.0

autho eth0:1
iface eth0:1 inet static
          address 81.7.84.36
          netmask 255.0.0.0
          gateway 81.7.84.1
          mtu 1492

I hadn't set mtu before. After setting it ping times decreased. (afterall it's dsl).
Also, what exatcly net/ipv4/tcp_low_latency = 1 in sysctl do?

-- 
Sincerely, Artūras Šlajus
ICQ: 157929934
Jabber: arturaz@akl.lt

Oh, and please'o'please use UTF-8! :-)



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Re: [LARTC] Random ping jumps

[R. Steve McKown]

On Thursday 08 January 2004 01:01 pm, Artūras Šlajus wrote:
> Map is at http://h2o.pieva.net/net.png

Ah, nice.

> > I'm also unclear about the pings that you've tried.  After you've shown
> > the network map, perhaps you can identify the two machines (and
> > interfaces) involved in each of the different ping tests you've
> > performed.
>
> The machine is totaly random.

What happens if you ping from the linux box to the linux box's default 
gateway?  If the problem doesn't exhibit in this test nor in any test between 
machines in your LAN, the problem is probably your providers: the DSL modem 
or something 'downstream' from it.  You should consider doing tests #2 and #3 
anyway as support for your position when you call your ISP to open a trouble 
ticket.

If the latency problem does exhibit pinging from the linux box to the default 
gateway, you haven't learned much yet.  Continue testing by removing 
variables, attempting to isolate the smallest 'configuration' that exhibits 
the problem.  The variables are: computers, hubs/switches, cables, and the 
like.  Here's some suggestions for testing:

1. plug the linux router directly into the DSL modem and ping from the router 
to the default gateway.  If the problem goes away, it's something in the 
hardware and cables that were 'bypassed' in this test.  You can continue this 
strategy to test into your network.  Read my security note below.

2. plug a PC, configured as the linux router's eth0:1 interface (with proper 
default gateway) and ping from the pc to the default gateway.  If the problem 
goes away, its probably the linux router (hardware or software).

3. If #1 and #2 don't cause it to go away, be sure you used a different cable 
in tests #1 and #2.  If the problem still doesn't go away, it's an issue for 
your network provider.

* security note *

Running both your LAN and the internet provider subnets on the same ethernet 
network puts you at a much greater security risk.  You should seriously 
consider installing a third network interface into your linux box and moving 
eth0:1's ip info to eth2.  Then plug the DSL modem into eth2 with a 
cross-over cable with no computers attached.

I'm guessing your thirty users using Windows.  If they have windows network 
enabled, they are all generating broadcast traffic.  That traffic will most 
likely be crossing the DSL modem (since it is bridging).  Aside from security 
implications, the local traffic that does get bridged is tying up your DSL 
bandwidth.  It seems unlikely that 30 PC's could saturate your 128kbps 
uplink, but I'm no expert on windows networking.  128kbps is not a huge pipe, 
so perhaps it's possible.  If so, the solution to your security problem is 
also the solution to the latency variability issue.  If this is the case, 
both tests #2 and #3 will not show the variability, since your local LAN is 
effectively removed from the test.

Hope this helps,
Steve

> x11@rasnet:~$ traceroute fortas.ktu.lt
> traceroute to fortas.ktu.lt (193.219.160.131), 30 hops max, 38 byte packets
>    1  adsl-213-190-40-129.takas.lt (213.190.40.129)  26.269 ms  23.333 ms 
> 25.156 ms 2  fe22-acc0-tai.kns.telecom.lt (212.59.7.233)  63.079 ms  33.146
> ms  26.117 ms 3  telecom-gw.is.lt (193.219.13.99)  35.978 ms  26.476 ms 
> 103.138 ms 4  litnet-gw.is.lt (193.219.13.98)  22.715 ms  24.531 ms 
> 209.984 ms 5  cat6506-p2-1.kttc.litnet.lt (193.219.62.125)  52.826 ms 
> 98.040 ms  81.609 ms 6  ktu-lan.litnet.lt (193.219.61.252)  38.696 ms 
> 182.582 ms  241.836 ms 7  fortas.ktu.lt (193.219.160.131)  215.523 ms 
> 126.815 ms  29.217 ms
>
> x11@rasnet:~$ traceroute cs.mes.lt
> traceroute to cs.mes.lt (193.219.67.253), 30 hops max, 38 byte packets
>    1  adsl-213-190-40-129.takas.lt (213.190.40.129)  748.174 ms  66.331 ms 
> 135.586 ms 2  fe22-acc0-tai.kns.telecom.lt (212.59.7.233)  21.645 ms 
> 21.588 ms  24.597 ms 3  telecom-gw.is.lt (193.219.13.99)  30.584 ms  31.065
> ms  29.612 ms 4  litnet-gw.is.lt (193.219.13.98)  24.602 ms  143.212 ms 
> 143.096 ms 5  cat6506-p2-1.kttc.litnet.lt (193.219.62.125)  292.196 ms 
> 163.870 ms  84.549 ms 6  ktu-lan.litnet.lt (193.219.61.252)  84.982 ms 
> 54.801 ms  69.143 ms 7  diz.ktu.lt (193.219.67.253)  33.831 ms  29.877 ms 
> 30.005 ms 64 bytes from diz.ktu.lt (193.219.67.253): icmp_seq=5 ttlY
> time4.8 ms 64 bytes from diz.ktu.lt (193.219.67.253): icmp_seq=6 ttlY
> time2.6 ms 64 bytes from diz.ktu.lt (193.219.67.253): icmp_seq=7 ttlY
> time3.1 ms 64 bytes from diz.ktu.lt (193.219.67.253): icmp_seq=8 ttlY
> time24 ms 64 bytes from diz.ktu.lt (193.219.67.253): icmp_seq=9 ttlY
> timeƒ6 ms 64 bytes from diz.ktu.lt (193.219.67.253): icmp_seq\x10 ttlY
> time…0 ms 64 bytes from diz.ktu.lt (193.219.67.253): icmp_seq\x11 ttlY
> time21 ms 64 bytes from diz.ktu.lt (193.219.67.253): icmp_seq\x12 ttlY
> time\x147 ms 64 bytes from diz.ktu.lt (193.219.67.253): icmp_seq\x13 ttlY
> time\x115 ms 64 bytes from diz.ktu.lt (193.219.67.253): icmp_seq\x14 ttlY
> time\x118 ms 64 bytes from diz.ktu.lt (193.219.67.253): icmp_seq\x15 ttlY
> time\x107 ms 64 bytes from diz.ktu.lt (193.219.67.253): icmp_seq\x16 ttlY
> time\x107 ms 64 bytes from diz.ktu.lt (193.219.67.253): icmp_seq\x17 ttlY
> time'2 ms 64 bytes from diz.ktu.lt (193.219.67.253): icmp_seq\x18 ttlY
> time12 ms 64 bytes from diz.ktu.lt (193.219.67.253): icmp_seq\x19 ttlY
> time\x102 ms 64 bytes from diz.ktu.lt (193.219.67.253): icmp_seq  ttlY
> time\x107 ms 64 bytes from diz.ktu.lt (193.219.67.253): icmp_seq! ttlY
> time\x114 ms 64 bytes from diz.ktu.lt (193.219.67.253): icmp_seq" ttlY
> time‰.8 ms 64 bytes from diz.ktu.lt (193.219.67.253): icmp_seq# ttlY
> time‘.2 ms
>
> x11@rasnet:~$ traceroute cs.bbd.lt
> traceroute to cs.bbd.lt (193.219.184.7), 30 hops max, 38 byte packets
>    1  adsl-213-190-40-129.takas.lt (213.190.40.129)  23.803 ms  24.813 ms 
> 56.163 ms 2  fe22-acc0-tai.kns.telecom.lt (212.59.7.233)  171.425 ms 
> 21.174 ms  24.321 ms 3  telecom-gw.is.lt (193.219.13.99)  27.882 ms  30.782
> ms  26.219 ms 4  litnet-gw.is.lt (193.219.13.98)  22.842 ms  23.025 ms 
> 24.079 ms 5  cat6506-p2-1.kttc.litnet.lt (193.219.62.125)  24.201 ms 
> 25.130 ms  27.256 ms 6  ktu-lan.litnet.lt (193.219.61.252)  26.811 ms 
> 27.362 ms  27.785 ms 7  193.219.184.7 (193.219.184.7)  27.928 ms  29.185 ms
>  28.067 ms x11@rasnet:~$ ping cs.bbd.lt
> PING cs.bbd.lt (193.219.184.7) 56(84) bytes of data.
> 64 bytes from 193.219.184.7: icmp_seq=1 ttl\x123 time\x133 ms
> 64 bytes from 193.219.184.7: icmp_seq=2 ttl\x123 time\x122 ms
> 64 bytes from 193.219.184.7: icmp_seq=3 ttl\x123 time\x118 ms
> 64 bytes from 193.219.184.7: icmp_seq=4 ttl\x123 time\x109 ms
> 64 bytes from 193.219.184.7: icmp_seq=5 ttl\x123 timer5 ms
> 64 bytes from 193.219.184.7: icmp_seq=6 ttl\x123 timef8 ms
> 64 bytes from 193.219.184.7: icmp_seq=7 ttl\x123 time\x120 ms
> 64 bytes from 193.219.184.7: icmp_seq=8 ttl\x123 time\x102 ms
> 64 bytes from 193.219.184.7: icmp_seq=9 ttl\x123 time‘.5 ms
> 64 bytes from 193.219.184.7: icmp_seq\x10 ttl\x123 time‘.7 ms
>
> > I had a similar problem recently.  Interestingly, it
> > turned out to be bad hardware.
>
> Another person told me that bad hw could be reason. But it works for
> LAN perfectly.
>
>   >  Moved the boot media to an identically
> >
> > configured machine and the problem went away.  Returned the boot media to
> > the original machine and the problem returned.
>
> Sad, but i can't do that :(
>
> My /etc/network/interfaces:
> auto eth0
> iface eth0 inet static
>           address 192.168.0.1
>           netmask 255.255.255.0
>
> autho eth0:1
> iface eth0:1 inet static
>           address 81.7.84.36
>           netmask 255.0.0.0
>           gateway 81.7.84.1
>           mtu 1492
>
> I hadn't set mtu before. After setting it ping times decreased. (afterall
> it's dsl). Also, what exatcly net/ipv4/tcp_low_latency = 1 in sysctl do?

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Re: [LARTC] Random ping jumps

[Artūras Šlajus]

Roy wrote:
 > Your network configutration is nonsense
 > you say
 >
 >>          address 81.7.84.36
 >>          gateway 81.7.84.1
 >
 >
 > trace shows
 >
 >  > traceroute to fortas.ktu.lt (193.219.160.131), 30 hops max, 38 byte
 > packets
 > yor computer>    1  adsl-213-190-40-129.takas.lt (213.190.40.129)  26.269 ms
 > 23.333 ms  25.156 ms
 > gateway >    2  fe22-acc0-tai.kns.telecom.lt (212.59.7.233)  63.079 ms
 > 33.146 ms  26.117 ms
 >
 >>   3  telecom-gw.is.lt (193.219.13.99)  35.978 ms  26.476 ms  103.138 ms
 >>   4  litnet-gw.is.lt (193.219.13.98)  22.715 ms  24.531 ms  209.984 ms
 >
 >
 > so everything incorect
Yes, that's DAMN strange...


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Re: [LARTC] Random ping jumps

[Artūras Šlajus]

R. Steve McKown wrote:

> What happens if you ping from the linux box to the linux box's default 
> gateway?  If the problem doesn't exhibit in this test nor in any test between 
> machines in your LAN, the problem is probably your providers: the DSL modem 
> or something 'downstream' from it.  You should consider doing tests #2 and #3 
> anyway as support for your position when you call your ISP to open a trouble 
> ticket.
It's not an ISP. Now it's morning and only 5 users online. The ping is flawless...
Well almost :)
Hostname                     Last  50 pings
  1. adsl-213-190-40-129.taka ..........>.......................................
  2. fe22-acc0-tai.kns.teleco ..........c......................................
  3. telecom-gw.is.lt         ..........b......................................
  4. litnet-gw.is.lt          .........3a......................................
  5. cat6506-p2-1.kttc.litnet .........b3...1a.................................
  6. ktu-lan.litnet.lt        .........c..........................1............
  7. diz.ktu.lt               .........>......1................................

Scale:  .:30 ms  1:46 ms  2:62 ms  3:99 ms  a:193 ms  b:283 ms  c:441 ms

> 2. plug a PC, configured as the linux router's eth0:1 interface (with proper 
> default gateway) and ping from the pc to the default gateway.  If the problem 
> goes away, its probably the linux router (hardware or software).
The problem goes away. I tried it here on my winxp box.

> * security note *
> 
> Running both your LAN and the internet provider subnets on the same ethernet 
> network puts you at a much greater security risk.  You should seriously 
> consider installing a third network interface into your linux box and moving 
> eth0:1's ip info to eth2.  Then plug the DSL modem into eth2 with a 
> cross-over cable with no computers attached.
Huh, would be great, but there is one but. Modem is at one house and server is at another :)
It's zyxel, maybe he has allow by mac or sth. I will look at his firmware setup.
Or maybe you have some thoughts how to connect server and modem? (about 200 m) :)

> I'm guessing your thirty users using Windows.  If they have windows network 
> enabled, they are all generating broadcast traffic.  That traffic will most 
> likely be crossing the DSL modem (since it is bridging).  Aside from security 
> implications, the local traffic that does get bridged is tying up your DSL 
> bandwidth.  It seems unlikely that 30 PC's could saturate your 128kbps 
> uplink, but I'm no expert on windows networking.  128kbps is not a huge pipe, 
> so perhaps it's possible.  If so, the solution to your security problem is 
> also the solution to the latency variability issue.  If this is the case, 
> both tests #2 and #3 will not show the variability, since your local LAN is 
> effectively removed from the test.

Yes, this may be true and solution. But is C class subnet traffic routed? I think it isn't.
It seems that when many users is browsing or doing normal day activities such as email checking
and irc download/upload? is saturated and it causes ping jumps. I will try to move ACKs into front
of queue and also prioritize some traffic. Bad that tc syntax is so unreadable.. Once it took 4 days
for me to write tc script ;-)

Also as roy mentioned, there is no such ip: 81.7.84.1
But if i set nexthop as my gw it says net unreachable... Maybe that gw has multiple addresses
or some magic is done on ISP side.

-- 
Sincerely, Artūras Šlajus
ICQ: 157929934
Jabber: arturaz@akl.lt

Oh, and please'o'please use UTF-8! :-)


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Re: [LARTC] Random ping jumps

[vica_s]

Hi All !

On Wed, 07 Jan 2004 23:26:01 +0200
Art <x11@h2o.pieva.net> wrote:

>    I've got this problem. There is an linux server with 2.4.24 kernel
> and pinging from him to internet (or from lan) ping randomly jumps up:
> 
> 64 bytes from fortas.ktu.lt (193.219.160.131): icmp_seq87 ttlY time0.0 ms
> 64 bytes from fortas.ktu.lt (193.219.160.131): icmp_seq88 ttlY time2.6 ms
> 64 bytes from fortas.ktu.lt (193.219.160.131): icmp_seq89 ttlY time4.9 ms
> 64 bytes from fortas.ktu.lt (193.219.160.131): icmp_seq90 ttlY time\x198 ms
> 64 bytes from fortas.ktu.lt (193.219.160.131): icmp_seq91 ttlY time@7 ms
> 64 bytes from fortas.ktu.lt (193.219.160.131): icmp_seq92 ttlY time@7 ms
> 64 bytes from fortas.ktu.lt (193.219.160.131): icmp_seq93 ttlY timeC0 ms
> 64 bytes from fortas.ktu.lt (193.219.160.131): icmp_seq94 ttlY time0.9 ms
> 64 bytes from fortas.ktu.lt (193.219.160.131): icmp_seq95 ttlY time1.6 ms




yesterday i have like that trouble when change ( test ) named.conf ,
try off DNS , and ping to ip.



Best regards
vica.

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Re: [LARTC] Random ping jumps

[Jurrie Overgoor]

Hello all,

> On Wed, 07 Jan 2004 23:26:01 +0200
> Art <x11@h2o.pieva.net> wrote:
>
> > I've got this problem. There is an linux server with 2.4.24 kernel
> > and pinging from him to internet (or from lan) ping randomly jumps up:
[snip]
>
> yesterday i have like that trouble when change ( test ) named.conf ,
> try off DNS , and ping to ip.

I don't think this is the problem. Afaik the dns server is only queried
once, to get the ip adres of the target host. After that, dns is left alone.
I suspect the problem to be a faulty cable or nic...

        Greetz -- Jurrie
        jurrie.overgoor@zonnet.nl

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