Verifying a connection between the AS/400 and RPM

To make a TCP/IP connection to RPM, the TELNET command may be used. To verify a connection, perform the following telnet test.

• At the AS/400 command prompt, type TELNET and press F4
• In the Start TCP/IP TELNET (TELNET) screen, press F9 to view "all parameters."
• In the Remote System field, type *INTNETADR. Enter the IP address of the RPM host in the Internet Address field.
• Locate the Port parameter and enter 515, then press Enter.

If RPM is configured to relax the 'port in range' requirement, this will input-inhibit the session if a connection is made. Close RPM (Windows 9x) or restart the RPM service (RPM Elite/Select) to release the AS/400 session. Then restart RPM and check the RPM log for new message.

If RPM is not configured this way, a new message should be displayed in the RPM log stating:
Client port xxxx out of range
Although this message is a warning, it verifies that a connection was made to RPM at port 515.

Source: http://www.brooksnet.com/faq/101-11.html

Sending broadcast packets in Java

Broadcasting is defined as sending a packet to all network nodes on a subnet. An IP network subnet mask divides an IP address into two parts: the network identifier and the node identifier. A broadcast address is defined as an IP address where all bits of the node identifier are set.

So, sending a broadcast packet from a Java program (or from a program in any other language, for that matter) simply requires you to specify the broadcast address as the destination for the packet.

Source: java-tips.org