Re: networking crash suddenly in my home LAN
Alex Samad <alex@samad.com.au> writes:
> On Wed, Jul 23, 2008 at 08:02:58PM +0200, Csanyi Pal wrote:
>> Andrew Sackville-West <andrew@farwestbilliards.com> writes:
>>
>> > On Wed, Jul 23, 2008 at 02:35:31PM +0200, Csanyi Pal wrote:
>> >> Andrei Popescu <andreimpopescu@gmail.com> writes:
>> >>
>> >> > On Wed,23.Jul.08, 13:31:13, Csányi Pál wrote:
>> >> >> I have at home a small LAN with Debian GNU/Linux Etch boxes.
>> >> >>
> [snip]
>
>> > /sbin/route
>> >
>> > when executed on the gateway machine.
>>
>> Kernel IP routing table
>> Destination Gateway Genmask Flags Metric Ref Use Iface
>> 91.102.231.32 * 255.255.255.240 U 0 0 0 eth2
>> 192.168.2.0 * 255.255.255.0 U 0 0 0 eth1
>> 192.168.1.0 * 255.255.255.0 U 0 0 0 eth0
>> default 46-231-102-91.r 0.0.0.0 UG 0 0 0 eth2
> [snip]
> looking at your route table I would suggest something like
>
> tcpduump -pni eth2 port 53 or host <insert the isps dns ip address here,
> the first one in the resolv.conf file>
>
> this will show you all the packets leaving via eth2 that are on port 53
> (dns) or are destined or have come from you isp's dns server.
>
> if this is working from the gateway, try it from one of the remote
> machines, the tcpdump should be still run on the gateway machine
This is working from gateway. I'm trying it from LAN behind the
gateway/firewall, from desktop machine.
tcpdump now shows traffic, when I ping www.google.com from desktop
machine.
I run on gateway command:
sudo tcpdump -pni eth2 port 53 or host 62.108.117.6
listening on eth2, link-type EN10MB (Ethernet), capture size 96 bytes
09:42:10.158205 IP 91.102.227.98.46197 > 62.108.117.6.53: 1661+ A?
www.google.com. (32)
09:42:15.153786 IP 91.102.227.98.50360 > 213.244.255.2.53: 1661+ A?
www.google.com. (32)
09:42:20.153200 IP 91.102.227.98.46197 > 62.108.117.6.53: 1661+ A?
www.google.com. (32)
09:42:25.152719 IP 91.102.227.98.50360 > 213.244.255.2.53: 1661+ A?
www.google.com. (32)
4 packets captured
4 packets received by filter
0 packets dropped by kernel
but I get error message on the command line on desktop (LAN):
$ ping www.google.com
ping: unknown host www.google.com
tcpdump now shows traffic, when I 'ping 62.108.117.6' from desktop
machine.
I run the command on gateway:
sudo tcpdump -pni eth2
09:46:56.951551 IP 91.102.227.98 > 62.108.117.6: ICMP echo request, id
63003, seq 10, length 64
09:46:57.083584 IP 91.102.227.98.50927 > 213.244.255.2.53:
58759+[|domain]
09:46:57.951463 IP 91.102.227.98 > 62.108.117.6: ICMP echo request, id
63003, seq 11, length 64
09:46:58.951366 IP 91.102.227.98 > 62.108.117.6: ICMP echo request, id
63003, seq 12, length 64
but at the command line on desktop machine I get nothing:
$ ping 62.108.117.6
PING 62.108.117.6 (62.108.117.6) 56(84) bytes of data.
Then I cancel it with Ctrl-C:
--- 62.108.117.6 ping statistics ---
13 packets transmitted, 0 received, 100% packet loss, time 12008ms
Well, I think that that something is wrong in my network setup, but
what?
--
Regards, Paul Csanyi
http://www.freewebs.com/csanyi-pal/index.htm
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