[Planetlab-users] question on tcpdump on new system

[Sapan Bhatia]

Hi Ning,

Your slice only sees packets that belong to it. If you ping another
host from within your slice, then the packets will appear in tcpdump.
In this case, the packets belong to the administrative context of the
system (and not your slice), so they are not reported via tcpdump.

Sapan

On 7/7/08, Ning Qu <quning at ymail.com> wrote:
> Hi, I have problems receiving packets using raw socket recently (after
>  system upgrade). The packets are sent back based on tcpdump on the
>  sender site, but no packets captured on planetlab's tcpdump. For
>  example, I am pinging one plnode from my own machine, and I do see the
>  reply:
>
>  64 bytes from planetlab-9.CS.Princeton.EDU (128.112.139.108):
>  icmp_seq=1 ttl=53 time=32.1 ms
>  64 bytes from planetlab-9.CS.Princeton.EDU (128.112.139.108):
>  icmp_seq=2 ttl=53 time=32.6 ms
>
>
>  but on planetlab node I received nothing from tcpdump:
>
>  @planetlab-9 ~]$ sudo /usr/sbin/tcpdump
>  tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
>  listening on eth0, link-type EN10MB (Ethernet), capture size 96 bytes
>
>  0 packets captured
>  0 packets received by filter
>  0 packets dropped by kernel
>
>  Can anyone help me on that?
>  thanks
>
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