=== Part 3: Network Connectivity & Network Service Troubleshooting Utilities===
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When our CentOS Troubleshooting network problems is an extremely important and frequent task that a Linux/Unix system provides any administrator performs on a daily basis! Since network services (such as file-server, print-servers, web-servers, and email-servers) depend on a networkconnectivity, those services are accessible through a port number. All as Linux/Unix sysadmin must be able to quickly and effectively pin-point sources of network services are configured problems in order to resolve them. Network service problems may not be accessed on entirely related to a "broken" network connection, but a particular port numberservice that is not running or not running correctly. By examining which ports are active on our system we can know what services (and points The following table lists the most common listing of attack) are available on our system. The ability utilities to examine this information is important for troubleshooting assist with detection of network connectivity or network services and securing our systemsservice problems to help correct the problem. One great tool for this is the '''netstatCommon Network Troubleshooting Tools''' command.
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