For most of us, networking-related tasks make up a large fraction of our system administration duties. Installing and configuring a network can be a daunting task, especially if you’re starting from scratch. However, monitoring and managing the network on an ongoing basis can be no less daunting, especially for very large networks. Fortunately, there are a variety of tools to help with this job, ranging from simple single-host network status utilities to complex network monitoring and management packages. In this section, we’ll take a look at representative examples of each type, thereby enabling you to select the approach and software that is appropriate for your site.
We’ll begin with the standard Unix commands designed for various
network monitoring and troubleshooting tasks on the local system. Each
command provides a specific type of network information and allows you
to probe and monitor various aspects of network functionality. (We’ve
already considered three such tools: ping and arp in Section 5.3 and
nslookup in Section 18.104.22.168 earlier in this
netstat command is the
most general of these tools. It is used to monitor a system’s TCP/IP
network activity. It can provide some basic data about how much and
what kind of network activity is currently going on, and also summary
information for the recent past.
The specific output of the
netstat command varies somewhat from system to system, although the basic information ...