[Xorp-users] Simple multicast configuration

Pavlin Radoslavov pavlin at icir.org
Fri Aug 10 22:00:48 PDT 2007


Sanchez <sanchezmk at yahoo.com> wrote:

>     How do I run tcpdump on LiveCD? It only allows me a few commands:
> 
> configure
> exit
> help
> ping
> ping6
> quit
> show
> traceroute
> traceroute6

Those are the xorpsh commands which you get when you login as
"xorp".

You need to login as user "root" and run tcpdump from the UNIX shell
instead of xorpsh. The root password will be the one you entered
when started the LiveCD.

You could do so by switching to another terminal by pressing Alt-F2,
Alt-F3, Alt-F4 and so on (and Alt-F1 to go back to the first
terminal).


>     I also stopped it before it loaded where it says
> "Hit [Enter] to boot immediately, or any other key for command prompt".
>     Here it also allows me only a few commands:
> 
> reboot
> heap
> bcachestat
> ....
> ...
> lsmod
> pnpscan
> 
>     I see the "ls" command is included, but not the "cd" command, so I can't even navigate to the "usr/sbin..." directory. Btw I'm not very proficient with freebsd, am I missing anything?

Those are the commands you can run before the FreeBSD kernel has
booted. You need to boot and configure XORP as usual.
After that Alt-F2 to switch to another terminal and login as "root".

Regards,
Pavlin

> 
> Pavlin Radoslavov <pavlin at icir.org> wrote: > On WinXP #1 I run:
> > C:\ssmping\ssmpingd
> > 
> > On WinXP #2 I run
> > C:\ssmping\asmping 224.1.1.1 169.254.2.20
> > 
> > and it starts to recive back in WinXP#2 only the unicast responses from WinXP#1, but not the multicast responses.
> >     Using Ethereal it can be seen that Windows does put the multicast traffic from the sending computer on the ethernet cable, and IGMP requests to join group on the receiving computer's cable.
> >     Meanwhile on LiveCD 1.4 we have:
> > 
> > xorp at LiveCD> show igmp group
> > Interface    Group        Source     LastReported Timeout V State
> > lnc0         224.0.0.2    0.0.0.0    169.254.1.2      222 2     E
> > lnc0         224.0.0.13   0.0.0.0    169.254.1.2      220 2     E
> > lnc0         224.0.0.22   0.0.0.0    169.254.1.2      222 2     E
> > lnc1         224.0.0.2    0.0.0.0    169.254.2.1      216 2     E
> > lnc1         224.0.0.13   0.0.0.0    169.254.2.1      216 2     E
> > lnc1         224.0.0.22   0.0.0.0    169.254.2.1      220 2     E
> > xorp at LiveCD> show pim join
> > Group           Source           RP             Flags
> > xorp at LiveCD>
> 
> Thank you for the info.
> It appears that XORP doesn't see any IGMP reports from the WinXP
> hosts, because the "show igmp group" doesn't show anything about
> multicast membership from the WinXP hosts.
> Also, the multicast traffic from the sender probably didn't
> reach XORP, otherwise "show pim join" should show (S,G) entry for
> the directly-connected senders.
> 
> Which machine did you use to run Ethereal? The Windows machine or
> the XORP box?
> If you used the Windows machine, please run "tcpdump" on the XORP
> box to make sure that the multicast packets (IGMP Joins and
> multicast data packets) really reach it.
> 
> FYI, in case you are not familiar with tcpdump, you could use the
> following command to print everything on interface lnc0:
> 
> /usr/sbin/tcpdump -i lnc0 -n -vvv -s 0 -x
> 
> See the tcpdump(1) manual page for details in case you need to
> filter and print only some of the packets.
> 
> Regards,
> Pavlin
> 
> 
> 
> 
>        
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