[quagga-users 9885] Re: Help RIPNG can send but not receive

Larry Marquis lmarquis at us.ibm.com
Fri Sep 5 18:57:14 IST 2008


Greg,

ip6tables was blocking the ripng msg receive. I am using centos5 Linux that
is a redhat clone.
The ripng msgs sarted  flowing when I disabled the ip6tables service with
"service ip6tables stop".
Then I added this line  "-A RH-Firewall-1-INPUT -p udp --dport 521 -j
ACCEPT"
 to /etc/sysconfig/ip6tables then restarted ip6tables
"service ip6tables start"

Now all is well.

Thanks for your help,
Larry


                                                                           
             Greg Troxel                                                   
             <gdt at ir.bbn.com>                                              
             Sent by:                                                   To 
             quagga-users-boun         Larry Marquis/Boca                  
             ces at lists.quagga.         Raton/Contr/IBM at IBMUS               
             net                                                        cc 
                                       quagga-users at lists.quagga.net       
                                                                   Subject 
             09/05/2008 08:55          [quagga-users 9884] Re: Help RIPNG  
             AM                        can send but not receive            
                                                                           
                                                                           
                                                                           
                                                                           
                                                                           
                                                                           





Larry Marquis <lmarquis at us.ibm.com> writes:

[formatting recovered]

> My problem is RIPng can send RIPng protocol messages but does not
> receive them..  I am monitoring the network with Wireshark and can see
> RIPng messages from other routers, and can see the RIPng messages
> broadcast by my RIPng node.
>
> In an effort to determine if the problem is my Linux configuration or
> Quagga RIPng I constructed a simple example program (based on the
> RIPng code) to read messages from the group address "ff02::9" on the
> RIPng port 521.
>
> The simple example program behaves like Quagga RIPng in that it does
> not receive the group multicast messages.
>
> So my assumption is that my Linux configuration is not correct for
> passing multicast group messages to my application (RIPng.) The sysctl
> value net.ipv6.conf.all.forwarding is 1. If there something else I
> need to do to enable receive of group multicast message ?
>
> I'm running Centos5  linux.

It sounds like multicast receive is broken, somewhere between quagga,
your kernel, and the ethernet interface.  If your test program doesn't
work, I would suggest getting trying to get support from Centos, and
only when that works reexamine quagga.

I presume you are doing an IP_ADD_MEMBERSHIP setsockopt, and that you
used netstat to look at the list of joined groups ('netstat -a' on BSD,
don't know about Linux).

On my NetBSD/sparc64 system, I can see ff02::9.

You can also try running tcpdump on the same interface, to see if
putting it in promiscuous mode works around bugs that may be present in
the multicast filter programming code.
(See attached file: attmy2md.dat)
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