The arping application is a simple command that will allow you to ping devices by hostname, IP address, or MAC address. The unfortunate part is that most device will not respond to the arp requests, which are directed broadcast ICMP echo requests, though there are some out there that do. I go into more detail below regarding pinging via MAC address by providing an example of the typical output, example output when a MAC address responds to the ICMP echo requests, and details about how to configure hosts to respond to these ICMP echo requests. I also show a couple of the switches available with arping and provide examples of using arping to ping devices by IP and host.
While working on the computer shop network I had to modify the configuration on our switch which is a Cisco Catalyst 2950. After making a bunch of changes I was testing things to make sure all was working as expected however after taking a break and logging back into the 2950 it appeared that all of the changes made had been reverted. I was assuming the Catalyst 2950 had lost power briefly which means all of the changes were lost since they had not been saved to the startup config yet. To verify my assumption I needed to look at the amount of time the switch had been up however “uptime” is not a valid iOS command. Below is information on the command used to verify uptime on a Cisco Catalyst 2950.
The file located in /etc/sysconfig/networking/profiles are created by the GUI network interface management tool. These files should not be edited manually and when changes need to be made they should be made directly to the files as shown below. CentOS 5 is easy to get around from the command line and it is beneficial to understand each of the below files if you are going to manage a server.
Need to make a change to hostname?
First modify /etc/sysconfig/network and modify the following line: