ping problems

[Aviv Greenberg]

Try netstat -s to checks for errors/drops on the WAN interface.
Anything interesting?

If a ping from the router always succeeds, and after some time fails
from the lan AND during failure you see the packets go from the lan
out to the wan but doesn't come back at all - it sounds like something
is wrong with the outgoing ping request packet.

Did you see any difference between a "goog" ping and "bad ping packets?

On Wed, May 27, 2009 at 10:05, Erez D <erez0001 at gmail.com> wrote:
>
>
> On Wed, May 27, 2009 at 9:41 AM, Aviv Greenberg <avivgnet at gmail.com> wrote:
>>
>> If you ping another destination during the "hang" - does it work?
>
> a download i started before the ping continues even after the ping is dead
>>
>> If you ifdown and ifup the interfaces (wan + lan) on the router after
>> a hang - is it released?
>> an icmp packet is short so i don't think this is the case but: what is
>> the MTU on the lan/wan?
>
> as you said, the ping packets are smaller then the mtu (and all are same
> size)
> also ping is connectionless, so it makes sense if the lost packets are
> spread randomly
> but not if in the beginning all pass and in the end all fail
>>
>>
>> Also, use a tool like mtr
>> http://en.wikipedia.org/wiki/Mtr_(My_traceroute) to detect any packet
>> loss along the route.
>
> mtr works from both router and lan
> there is some packet lost on the closer servers, but none at the target
> but it is the same for both router and lan.
>
> thanks,
> erez.
>>
>>
>> 2009/5/27 Erez D <erez0001 at gmail.com>:
>> > hi
>> >
>> > i have an openwrt (linux) router, with regular firewall rules (nat,
>> > related+established,clamp-mss-to-pmtu, etc).
>> >
>> > if i ping from the router to the internet, it works ok
>> > however if i ping from inside my lan to the internet, the first 30-70
>> > pings
>> > works, then it stops working (i.e. 100% packet lost after the first
>> > 30-70)
>> > using tcpdump inside my router shows the icmps going through the wan
>> > interface but none come back.
>> >
>> > any idea ?
>> > erez.
>> >
>> > _______________________________________________
>> > Linux-il mailing list
>> > Linux-il at cs.huji.ac.il
>> > http://mailman.cs.huji.ac.il/mailman/listinfo/linux-il
>> >
>> >
>>
>>
>>
>> --
>>
>> Frank Lloyd Wright  - "TV is chewing gum for the eyes." -
>> http://www.brainyquote.com/quotes/authors/f/frank_lloyd_wright.html
>
>



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