Hostname and Linux version

The uname command can print some basic information about your Linux system. This information can include:

Operating system name (i.e., Linux)
System's host name
Linux release number
Current date and time
Processor type

The following is an example of the uname -a command (the -a prints all the information at once):

$ uname -a

Linux mycomputer 2.4.6-3.1 #1 Sat Oct 27 19:09:11 EDT 2001 i686 unknown

The system's hostname is used to identify your computer (in particular, it is used by remote systems to contact you over a network). The Linux release number (2.4.6-3.1) identifies the release of the Linux kernel that you have installed. Check this number to make sure you have the latest kernel. You can change your computer name using the hostname command as follows:

# hostname yourcomputer

Hostname is read automatically

The hostname is read automatically by different programs that need to indicate what computer is being used. For example, your shell command line prompt probably automatically displays the hostname. You can also print other information that relates to how your computer is named from the perspective of the network. For example, dnsdomainname lists your domain name (used for the Internet). If your computer uses NIS services, you can print your NIS domain name with the domainname command.

arp-a command output

1) These are the hostnames returned by arp

2) These are the pairings of IP addresses and Ethernet addresses. Note that because the first three numbers of each IP address are the same, the netmask is most likely 255.255.255.0.

3) This indicates the interface device and type. Each computer is using the first Ethernet device, `eth0. [ether]` shows the type of interface device, which is Ethernet.

arpwatch: Contains the arpwatch utility for tracking Ethernet/IP address pairings.