How to Run Tcpdump From Java

Tcpdump can expedite the process of network traffic analysis.

Tcpdump is a command line utility that analyzes TCP/IP (transmission control protocol/Internet protocol) data as it is exchanged over a computer's network connection. Tcpdump is used primarily by systems administrators and other IT professionals to monitor data on their network, but can also be used to monitor the health of a network itself. Tcpdump runs on UNIX and many UNIX-derived operating systems, including Linux, FreeBSD and Mac OS X, and can be incorporated into programs or scripts through the use of the language-specific appropriate method. In Java, the appropriate method belongs to class Runtime.

Instructions

1. Determine the options with which you want to call Tcpdump by consulting the Tcpdump user's manual. To access the user's manual, open the Terminal program and type "man tcpdump". The list of options (or "flags") will appear, along with explanations for each of them. For example, if you want Tcpdump to write to a file, you would use the "-w" flag, resulting in the command "tcpdump -w examplefile," where "examplefile" is the file to which output will be written.

2. Create a Process object by adding the code "Process process;" to your Java code.

3. Give the Process object the value of a Runtime object whose input is your Tcpdump command from Step 1 by adding the code "process = Runtime.getRuntime.exec("tcpdump -w examplefile");" to your Java code. Essentially, Tcpdump is now being executed by your Java program.

4. Close your Tcpdump stream by adding the code "process.destroy();" to your Java code.

References

• TCPDUMP &LIBPCAP: TCPDUMP
• Oracle: Class Runtime