Understanding networking concepts is a more advanced concept for most system administrators, but it is essential to being successful. In this activity, the we will use the netcat (`nc`) utility to generate network traffic between two servers and view that traffic’s appearance in a tool called `iptraf-ng`.
Learning Objectives
Successfully complete this lab by achieving the following learning objectives:
- Install Client Utilities
We’ve got to install the two packages that the team will use to generate and monitor traffic. Let’s use YUM to get it done:
[root@server1]# yum install iptraf-ng ncRepeat this on the other server:
[root@server2]# yum install iptraf-ng nc- Create the Traffic Log File
On the first server, let’s run
iptraf-ngand go underConfigure...In the menu, don’t forget this isn’t a menu we control with a mouse — it’s all keyboard. Make sureLoggingis toggled toOn. Set the log file path to:home/cloud_user/traffic_log.txt. Then go into IP traffic monitor. In the next menu, select eth0. Once we press Enter the logging will start.Listen for Traffic
Let’s open a second terminal into
server1and runsudo suright off. Once we’re there, we’re going to start netcat listening on post 2525 with this:[root@server1]# nc -l 2525Send Some Traffic
Now, let’s start talking. Back in the
server2window we’ve got open, send netcat traffic toserver1with this (wherex.x.x.xis the internal IP ofserver1that we’ll see on the hands-on lab overview page):[root@server2]# nc x.x.x.x 2525We’ll just land at a blinking cursor below the prompt, but we can type a message there and press Enter. Once we do, it will show up back in the window we’re listening in on
server1. A bunch of messages sent fromserver2would look like this:[root@server2]# nc x.x.x.x 2525 test test testing This is a testOn
server1, they would look like this when they arrive:[root@server1]# nc -l 2525 test test testing This is a testThat should be enough traffic for what we’re doing. On
server2, press Ctrl + C to kill thenccommand we’ve got running and flip back over to the terminal we were runningiptraf-ngin. Press x to stop the monitoring and get out, then choose Exit from the main menu.Examine the Log
On
server1, if we runls /home/cloud_userwe should seetraffic_log.txtlisted in the output. Read that to see if it was capturing what we need:[root@server1]# less /home/cloud_user/traffic_log.txtWe should see some log entries showing traffic going from
server2toserver1on port 2525.
