3.4. Troubleshooting with TCP/IP Utilities

After you have TCP/IP installed and configured and you have your TCP/IP network running, you need to be able to troubleshoot the network. When problems arise on a Windows network, you can use some of the following commands to do your troubleshooting:


  • PING






The following sections discuss these popular TCP/IP utilities that are used to troubleshoot TCP/IP connectivity.


On Windows systems, you can run the ipconfig (IP configuration) utility, which shows you the current TCP/IP configuration of the Windows desktop, such as the IP address, subnet mask, and default gateway. If the computer is a DHCP client, ipconfig identifies the server that has given the IP address and also shows how long the IP address will be used by the client. Table 3-3 shows some of the switches supported by the utility ipconfig.exe.

Table 3.3. IPCONFIG Switches
/?Shows a list of switches supported by ipconfig.exe and a brief description of each switch
/allShows all TCP/IP information — for example, DHCP lease period and the DNS server
/releaseReleases the current IP address information assigned by the DHCP server
/renewRequests new IP address information from the DHCP server
/displaydnsDisplays the DNS resolver cache which stores recent results from DNS queries
/flushdnsClears the DNS resolver cache

For example, to use the ipconfig utility and view just the basic TCP/IP settings, you type the following ...

Get CompTIA A+® Certification All-In-One For Dummies®, 2nd Edition now with O’Reilly online learning.

O’Reilly members experience live online training, plus books, videos, and digital content from 200+ publishers.