Hi Larry,
>I installed Redhat Linux 5.2 and the kernel version is 2.0.36. I can't find
>kernel config file, but during the installation, I selected "IP MULTICAST".
Kernel config file is usually '/usr/src/linux/.config'. But you don't need
to check it anymore because your kernel is multicasting capable according to
the output you have got from ifconfig.
>No, I don't have this file. Through the execution of 'netstat -r' the
kernel
>IP routing table contains two entries:
>167.10.0.0 and 127.0.0.0. There is no 224.0.0.0 entry. Is this OK?
Acutally, you need this static route. I don't know how RedHat configures
static routes. But usually a file like '/etc/route.conf' is read during
starting routing services during startup. My system (SuSE Linux 6.1) uses
'/etc/route.conf' which is read by '/sbin/init.d/route'. Your system
probably is different. Maybe you check '/etc/init.d/route' for the name of
the static routes file.
But to test your software you might add the route manually with (as root):
route add net 224.0.0.0 netmask 240.0.0.0 dev eth0
if the name of your network interface is eth0 (it is according to your
ifconfig).
If you then check 'netstat -r' again there should be an entry like
224.0.0.0 * 240.0.0.0 U 0 0 0 eth0
or
BASE-ADDRESS.MC * 240.0.0.0 U 0 0 0 eth0
This route is mandatory otherwise the protocol driver doesn't know where to
send the multicast request to. Although Java says 'invalid operation' the
right error message should be 'network unreachable' which means the protocol
driver doesn't know how to reach the network with the multicast addresses.
I really think this is the problem because I had exactly the same.
Rudy
-----Original Message-----
From: Larry Hsiao <[EMAIL PROTECTED]>
To: Rudi Streif <[EMAIL PROTECTED]>
Date: Wednesday, July 28, 1999 12:43 PM
Subject: Re: Invalid DatagramSocket option
>Rudy,
>
>Thanks for the info.
>
>> You need to check if your kernel and your network interface is multicast
>> capable.
>
>I checked ifconfig -a, it shows:
>eth0 UP BROADCAST RUNNING MULTICAST MTU:1500 Metric=1.
>
>Also, executed "dmesg | less" from the command line, it shows:
>Linux IP multicast router 0.07
>
>> Your kernel needs to be compiled with the option 'CONFIG_IP_MULTICAST=y'.
>> And your kernel should be at least a 2.0.x version if you didn't patch
it.
>
>I installed Redhat Linux 5.2 and the kernel version is 2.0.36. I can't find
>kernel config file, but during the installation, I selected "IP MULTICAST".
>
>> Check your network interface configuration with 'ifconfig'. For every
>> multicast capable interface it displays the flag 'MULTICAST'.
>
>The eth0 interface shows 'MULTICAST'.
>
>> Check your /etc/route.conf file. The multicast route must be set to
>> something like this if you want to use multicast on eth0:
>> 224.0.0.0 0.0.0.0 240.0.0.0 eth0
>
>No, I don't have this file. Through the execution of 'netstat -r' the
kernel
>IP routing table contains two entries:
>167.10.0.0 and 127.0.0.0. There is no 224.0.0.0 entry. Is this OK?
>
>> If all of this is ok it should work.
>
>Any other clues?
>
>Thanks.
>Larry Hsiao
>
>
>
>
>
>
>
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