How configure firewall to allow me to send/receive multicast?

I’m writing a multicast client/server in Java, but the firewall is blocking it (I confirmed this by stopping the firewall and suddenly the packets are received). How do I configure the firewall to allow me to send/receive multicast packets?

Allow packets with IP addresses in the range 224.0.0.0/4 through.

Thanks. :slight_smile: How do I do that? In the firewall app, I can’t seem to find a place to do that.

You probably have to add a rule to allow packets from 224.0.0.0/4 in. Out is generally not blocked. I don’t use SuSEFirewall2 so you’d have to investigate this yourself. (My machine is inside a perimeter firewall, and I play with networking on my LAN.)

The only thing that worked was under “Allowed Services” to open port 4997 (the port I’m using for the Multicasting) externally. But it didn’t give me a way to tie it to an IP address. Any idea how to do that?

I tried the following but they don’t work:


1. Adding a "Custom Rule" with source address:
   224.0.0.1   UDP
   224.0.0.1   TCP
   224.0.0.0/24   UDP
   224.0.0.0/24   TCP
   192.168.1.11   TCP   //This is the server's address
   192.168.1.11   UDP

None of them work.

2. Under Broadcast Configuration:

"Accepting the broadcast reply":

224.0.0.1    All UDP
224.0.0.1    All TCP
0/0            All UDP
0/0            All UDP

Perhaps you don’t really need the multicasting addresses at all. Without knowing what the software specifies, and whether its idea of multicasting is the accepted definition, it’s hard to say.