Re: NEWBIE QUESTION : Why does the installer not detect multicast on interfaces

You don't have to use multicast for anything if you don't like. You  
can unicast your entire Jini setup.

On the flip side, I used to run Jini on Fedora, Debian, Ubuntu and  
others with no issues. It sounds like you have a lot of custom network  
configuration going on if you can't get multicast to work. In all my  
experience, multicast was enabled by default on all Linux distros and  
if it wasn't, you could alsways change that configuration using the  
standard GUI interfaces.

My first guess would be that your IP tables are dropping these packets  
and need to be reconfigured. I'd also take a step back and setup a  
simple Java program that sends out a multicast packet and another  
simple java program that receives them. See if you can do it outside  
of Jini. This might reveal some bad Jini config.

Lastly, if you can't get multicast to work at all, I'd consider  
dropping all your IP tables, reseting your interfaces and starting  
fresh. Generally after major interface changes, you might need to  
reboot as well. The init.d scripts to restart your network aren't  
always 100% reliable.

-bp

On Feb 13, 2009, at 10:31 AM, Pranav Vaidya wrote:

> Hello,
>
> I am a newbie with jini and I have a problem installing jini on  
> linux. I
> have a laptop with Fedora core 9 on it. I tried installing jini on the
> windows xp (sp2) 32 bit partition and the jini installation was  
> successful
> in that it went ahead and showed me that the both eth0 and wlan0 are
> multicast enabled and jini will use them for service discovery. I  
> have used
> this to experiment with Jini on windows. However, I wanted to shift to
> experimenting on linux too.
>
> However, I have a problem installing the same on my linux partition.  
> The
> following are the machine details.
>
> $> uname -a
> Linux localhost.localdomain 2.6.27.12-78.2.8.fc9.i686 #1 SMP Mon Jan  
> 19
> 20:14:35 EST 2009 i686 i686 i386 GNU/Linux
>
> $> java -version
> java version "1.6.0_11"
> Java(TM) SE Runtime Environment (build 1.6.0_11-b03)
> Java HotSpot(TM) Server VM (build 11.0-b16, mixed mode)
>
> $> ifconfig
> eth0      Link encap:Ethernet  HWaddr xx:xx:xx:xx:xx
>         UP BROADCAST MULTICAST  MTU:1500  Metric:1
>         RX packets:0 errors:0 dropped:0 overruns:0 frame:0
>         TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
>         collisions:0 txqueuelen:1000
>         RX bytes:0 (0.0 b)  TX bytes:0 (0.0 b)
>
> lo        Link encap:Local Loopback
>         inet addr:127.0.0.1  Mask:255.0.0.0
>         inet6 addr: ::1/128 Scope:Host
>         UP LOOPBACK RUNNING  MTU:16436  Metric:1
>         RX packets:5710 errors:0 dropped:0 overruns:0 frame:0
>         TX packets:5710 errors:0 dropped:0 overruns:0 carrier:0
>         collisions:0 txqueuelen:0
>         RX bytes:285916 (279.2 KiB)  TX bytes:285916 (279.2 KiB)
>
> wlan0     Link encap:Ethernet  HWaddr xx:xx:xx:xx:xx
>         inet addr:xx:xx:xx:xx:xx  Bcast:xx.xx.xx.xx  Mask:xx.xx.xx.xx
>         inet6 addr: xx:xx:xx:xx:xx Scope:Link
>         UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
>         RX packets:1982 errors:0 dropped:0 overruns:0 frame:0
>         TX packets:812 errors:0 dropped:0 overruns:0 carrier:0
>         collisions:0 txqueuelen:1000
>         RX bytes:712819 (696.1 KiB)  TX bytes:132136 (129.0 KiB)
>
> wmaster0  Link encap:UNSPEC  HWaddr xx:xx:xx:xx:xx
>         UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
>         RX packets:0 errors:0 dropped:0 overruns:0 frame:0
>         TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
>         collisions:0 txqueuelen:1000
>         RX bytes:0 (0.0 b)  TX bytes:0 (0.0 b)
>
> I have tried installing jini using jini2_1.bin as well as  
> jini2_1.jar and
> both of them at the end of the installation tell me the following.
>
> These network interfaces were found on this system:
> wlan0: MULTICAST DISABLED
> lo: MULTICAST DISABLED
> By default Jini multicast discovery will use all of the network  
> interfaces
> that are multicast enabled.
> WARNING: none of the network interfaces appear to have multicast  
> enabled.
> Jini multicast lookup discovery may not function properly.
>
> Here is my problem:
> The kernel seems to be compiled for multicast support  (as can be  
> seen from
> ifconfig) for both  interfaces I might use namely eth0 when I am in  
> the lab
> and wlan0 when I am at home (at home I use a wireless router  
> connected to
> DSL modem).
>
> As per http://www.linuxdevices.com/articles/AT3724430088.html
> I have done the following
> $route add -net 224.0.0.0 netmask 240.0.0.0 dev eth0
> $ifconfig lo multicast
> $ifconfig eth0 multicast
>
> Also, I can see this information in when I list this in route -n. I  
> have
> also changed my IP tables to allow the IP multicast traffic. I am at  
> my wits
> end in that I am not sure if this is all that is needed and if yes  
> why is
> the installer giving me this error. As far as I understand from what  
> I read
> about Jini is that IP multicast is essential for both service  
> discovery as
> well as peer lookup. IMHO, this is very important.
>
> I was wondering what the issue might be for the aforementioned  
> error. Any
> help regarding is deeply appreciated.
>
> And yeah, the same situation applied for a desktop linux machine  
> with the
> same kernel and FC9 that I have in my lab while the windows desktop  
> machine
> in my lab works fine.
>
> Pranav
> -- 
> View this message in context: http://www.nabble.com/NEWBIE-QUESTION-%3A-Why-does-the-installer-not-detect-multicast-on-interfaces-tp22001045p22001045.html
> Sent from the Sun - Jini-Users mailing list archive at Nabble.com.
>
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