On Wed, Apr 8, 2009 at 9:00 PM, Ponnapalli Hari Gopal
<[email protected]> wrote:
Hi,
I am bit new to the network programming. I am developing a server based
on Mina using datagram sockets. I am bit confused with the datagram
sockets here. When I start an instance of the server on a port (say 1812)
it starts. However, when I run a second instance of the server on same
port, it also binds to that port successfully. I am expecting that the
bind should fail here as the port is already in use, the TCP/IP way. Is
it an expected behavior of UDP datagrams?
If this is the expected behavior, how do I know which instance of the
server receives the packets?
See this
http://www.softlab.ntua.gr/facilities/documentation/unix/unix-socket-faq/unix-socket-faq-2.html#time_wait
This is TCP stack behaviour. You may want to set reuseaddress to false
I will check this. Is it a default beavior in DatagramAcceptor of Mina?
Basically, I am trying to develop a RADIUS server on top of Mina. The
server is up and running. However, if there are multiple instances of the
server running, sometimes I am facing strange behavior in terms of none
of the servers are receiving the packets.
All of them should run on different ports or on different machines,
else you have to develop a protocol above TCP for demultiplexing
I think, my explanation was confusing. What all I want is a single
instance of the server running on a given machine on a given port. If
any attempt made to run a second instance on same machine, same port, it
should fail. However, with the code I shared, the second instance also
runs, without throwing exception. So, I want to correct that behavior.
Can someone provide any pointers on how to developa datagram server
reliably. I also want to provide some start, shutdown scripts that allows
the users to start, stop the server. For this, any guidance on what is
the approach to be
Can plan to use JMX or simple shell scripts will do.
followed. If I start the server in a new thread, and close the main
program, the server thread also (being child) is getting closed. So,
do I need to start a separate port on which server listens for
administrative commands like start, shutdown?
If your close the main program means exits the JVM, no Java program
can run. You should think of running the program as background process
Yes, precisily. As the exit main is end of JVM, I could not leave the
server running. Will check how to run a java program as a background
process.
In such case how to provide authentication of it? Or shall I need to
use some shared memory (flag) that will be used by both server and
startup/shutdown scripts. In such case the server requires constant
polling of the shared variable to start/stop the server.
Also does the RADIUS need to be mandatarily supported only on UDP?
RFC's are better place to look for this.
Sorry for my stupid questions, but, any ideas/guidance on same is highly
appreciated.
Regards,
Hari
--
thanks
ashish
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