Basic Networking Practice

In my current position, there is not much work for me to practice my networking skills, so I feel as if I might lose some proficiency with Cisco’s CLI and all the regular commands. I started up my EVE-NG VM again and went to work trying out some basic router configurations, using it as a DHCP server, etc.

EVE-NG’s website has some good documentation on getting an IOS loaded into the VM, but there’s some hiccups I experienced on the way.

It can be hard to have the exact image/version that is known to be supported on EVE-NG. For instance, in the documentation on EVE=NG’s website, it mentions using c3725-adventerprisek9-mz.124-15.T14.bin as the supported version, but I had c3725-adventerprisek9-mz124-15.bin. Notice the lack of .T14 in mine. Luckily for me if you just alter file and folder names to accommodate the missing .T14 it worked fine.

However this isn’t always the case, because in my first attempt I tried to use c7200-adventerprisek9-mz.124-24.T5.image, which isn’t the supported c7200-adventerprisek9-mz.152-4.S6.bin or c7200-adventerprisek9-mz.152-4.S2.bin images. At the end of the day I was just glad to get one of the images working.

One more thing to note. In the documentation it mentions calculating the IDLE-PC usage in order to lower the CPU usage of the simulated router. My first router’s best/highest tested IDLE-PC value was 0x61499868 but the default value was something else which would make all other routers have a higher default CPU usage. While it does say where to put the information for the node you just did it on, it does not say how to make that the default configuration.

I found this blog which said that in order to make it default, you had to go change the IDLE-PC value of the template. In my case, mine was a little different to the blod and I used:

nano /opt/unetlab/html/templates/intel/c3725.yml

Now all my future nodes will have the lowest CPU usage on the VM as tested.