UDP Broadcast

[Michael Wüst <mwuest@gev5.gotdns.org>]

Hi @ all,

I have the following problem:

System is Debian Linux Sarge with Kernel 2.4.29. I want to
send and receive UDP Broadcasts. I have no firewall
installed, the system is very basic.

The Broadcasts need to be received from systems not being
in the same subnet and to be sent to systems not being in
the same subnet.

I am using sockets with SO_BROADCAST enabled. The packet
is sent out and received, but only in the same subnet, not
in other subnets being on the same physical network.

What am I doing wrong? What is exactly the meaning of the
broadcast value in /etc/network/interfaces? Are there any
specific parameters to be set? Are there any special kernel
issues that need recompiling? Is the broadcast adress
255.255.255.255 correct?

Maybe someone has any for functionality approved command
line test program that sends out any "text" by UDP broadcast
so that I can check whether the linux is blocking or my
configuration is or my programing is wrong.

Any help appricated. Links to FAQs, PDFs appreciated too.

Thanks,
bye,
Michael.