[LARTC] Random ping jumps

[R. Steve McKown]

Can you provide some more detail on your network configuration?  I'm unclea=
r=20
if the linux server is your internet router or just another client computer=
=20
on your local LAN, where the test pings to "the internet" are going (i.e.=20
nexthop router, etc.), and if/where CIPE tunnels are involved in the=20
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=
=20
network map, perhaps you can identify the two machines (and interfaces)=20
involved in each of the different ping tests you've performed.

I had a similar problem recently.  A linux-based router with four interface=
s=20
serving three local LANs and a T-1 (via the provider's router) to the=20
internet.  The router was forwarding traffic between all combinations of=20
networks (that were allowed by rule) correctly, except between LANs 1 and 2=
=2E =20
In this case, pings would vary much as in your case.  Interestingly, it=20
turned out to be bad hardware.  Moved the boot media to an identically=20
configured machine and the problem went away.  Returned the boot media to t=
he=20
original machine and the problem returned.

On Wednesday 07 January 2004 02:26 pm, Art=C5=ABras =C5=A0lajus 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_seq=3D387 ttl=3D59
> time=3D30.0 ms 64 bytes from fortas.ktu.lt (193.219.160.131): icmp_seq=3D=
388
> ttl=3D59 time=3D32.6 ms 64 bytes from fortas.ktu.lt (193.219.160.131):
> icmp_seq=3D389 ttl=3D59 time=3D34.9 ms 64 bytes from fortas.ktu.lt
> (193.219.160.131): icmp_seq=3D390 ttl=3D59 time=3D198 ms 64 bytes from
> fortas.ktu.lt (193.219.160.131): icmp_seq=3D391 ttl=3D59 time=3D407 ms 64=
 bytes
> from fortas.ktu.lt (193.219.160.131): icmp_seq=3D392 ttl=3D59 time=3D407 =
ms 64
> bytes from fortas.ktu.lt (193.219.160.131): icmp_seq=3D393 ttl=3D59 time=
=3D430 ms
> 64 bytes from fortas.ktu.lt (193.219.160.131): icmp_seq=3D394 ttl=3D59
> time=3D30.9 ms 64 bytes from fortas.ktu.lt (193.219.160.131): icmp_seq=3D=
395
> ttl=3D59 time=3D31.6 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 =3D 1
> net/ipv4/icmp_ignore_bogus_error_responses =3D 1
> net/ipv4/icmp_echo_ignore_broadcasts =3D 1
> net/ipv4/tcp_syncookies =3D 1
> net/ipv4/tcp_timestamps =3D 0
> net/ipv4/tcp_window_scaling =3D 0
> net/ipv4/tcp_sack =3D 0
> net/ipv4/tcp_fin_timeout =3D 30
> net/ipv4/tcp_keepalive_time =3D 1800
> net/ipv4/tcp_low_latency =3D 1
>
> Thanks for any thoughts.
>
>
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