Are you experiencing problems with your computer network? Are these error messages appearing?:

• Unable to clear the DNS cache
• Unable to renew your IP address
• An operation was performed on something that is not a socket
• Unable to clear the ARP cache

If so, here are some potential solutions for Windows XP/Vista.

1. Check to make sure your computer is on and is connected to a network.
2. Be aware that Windows has a built in function to repair a network connection. This function can give valuable information in the form of an error message if you know what you are looking for. Some common error messages given are:
   • Unable to clear the DNS cache
   • Unable to renew your IP address
   • Unable to clear the ARP cache
3. Deal with a message that states “Unable to clear the DNS cache.” When you get the message “Unable to clear the DNS cache”, this usually means that the DNS client service has been disabled. Follow these steps as an administrator to re-enable it:
   • Open the Services MMC plugin, located under Administrative Tools in the Control Panel;
   • Find the “DNS Client” service in the list presented and enter it’s properties by double-clicking it;
   • Change the Startup Type from Disabled to Manual or Automatic then click apply;
   • Either reboot or click “Start” to start the service;
   • Verify by attempting to repair the connection again.
4. Fix a problem related to an IP address. If the repair process reports that it has been ‘Unable to obtain an IP address’, it is probable that more information can be obtained through the command line. Open a Command Prompt by going to Start > Programs > Accessories > Command Prompt, then type ‘ipconfig /renew’ to attempt to obtain an IP address from the command line.
5. Follow up the error messages that will likely appear. There is a high likelihood of an error message similar to the one below occurring, the remainder of the guide will focus on this error.
   • “An operation was performed on something that is not a socket”
6. Fix the error message “An operation was performed on something that is not a socket.”: This is a Winsock corruption generally due to spyware. The fixes are:
   • A simple fix can be done with Windows XP SP2 or Windows Vista (Start > Run > cmd > netsh winsock reset), then reboot your computer. If you do not have SP2, you can download a small program to reinstall Winsock: winsockfix.exe.

Do you need to shutdown a server or other remote computer? Need to do this from the convenience of your own PC? Here’s how to shutdown a remote Windows computer from your own desktop.

1. Open the command prompt. This may be done by clicking on the “Start” button, and selecting “Run”.
2. Type in cmd and press Enter.
3. Type in shutdown -m \\computername, replacing “computername” with the name of the computer you wish to shutdown or the computers ip address.
4. Experiment with the shutdown command’s switches.
   • -r will force a restart, disabling any services or user interaction from interrupting it.
   • -c “comment” will force a comment to appear on the system being shutdown.
   • -t xx will force a timeout for “xx” seconds. For example, -t 60 would perform a shutdown after a 60 second timeout.
   • -a will abort the shutdown
   • A full command example: shutdown -m \\myserver -r -c “This system will shutdown in 60 seconds” -t 60
5. Another method is to
   • type shutdown -i in the run window.
   • Click the “Add” box and type the name of the computer you want to shutdown or it’s IP address. You can select what you want the computer to do.
   • In this mode, it is NECESSARY to add a comment. Finally press “OK”

   Note:

• For a complete list of the switches (options) for the “shutdown” command, type in shutdown ? inside of a command prompt window.
• The target computer and your PC need to be in the same Domain or Workgroup for this to function correctly.
• This will only work on Microsoft Windows based systems. Linux and Mac will require different terminal commands.
• You may also run this shutdown command directly from the “Run” dialog. Opening a command prompt is merely a convenience in case you happen to type in the wrong system name or need to search for the name of the system to shutdown.

These instructions show how to connect two computers for the purpose of sharing data. This will let you share files and folders, printers, play network games, etc.

1. Choose a Network Address
   • Any network address will do for this purpose, so long as you understand the basics of how IPv4 works as explained below.
   • IPv4 (IP ver. 4) addresses are written like this: xxx.xxx.xxx.xxx (four numbers separated by three dots), in all RFC-1166 compliant countries. Each number ranges from 0 to 255. This is known as “Dotted Decimal Notation” or “Dot Notation” for short. The address is divided into two portions: the network portion and the host portion.

     For “Classful” networks, the network and host portions are as follows:
     (”n” represents the network portion, “x” represents the host portion)

     When the first number is 0 to 127 - nnn.xxx.xxx.xxx (ex. 10.xxx.xxx.xxx)
     These are known as “Class A” networks.

     When the first number is 128 to 191 - nnn.nnn.xxx.xxx (ex. 172.16.xxx.xxx)
     These are known as “Class B” networks.

     When the first number is 192 to 223 - nnn.nnn.nnn.xxx (ex. 192.168.1.xxx)
     These are known as “Class C” networks.

     When the first number is 224 to 239 - The address is used for multi-casting.

     When the first number is 240 to 255 - The address is “experimental”.

     The network portion specifies a network; the host portion specifies an individual device on a network.

     For any given network:

     • The range of all possible host portion numbers gives the Address Range.
       (ex. 172.16.xxx.xxx the range is 172.16.0.0 to 172.16.255.255)
     • The lowest possible address is the Network Address.
       (ex. 172.16.xxx.xxx the network address is 172.16.0.0)
       This address is used by devices to specify the network itself, and cannot be assigned to any device.
     • The highest possible address is the Broadcast Address.
       (ex. 172.16.xxx.xxx the broadcast address is 172.16.255.255)
       This address is used when a packet is meant for all devices on a specific network, and cannot be assigned to any device.
     • The remaining numbers in the range are the Host Range.
       (ex. 172.16.xxx.xxx the host range is 172.16.0.1 to 172.16.255.254)
       These are the numbers you can assign to computers, printers, and other devices.
       Host Addresses are individual addresses within this range.
2. Connect the two computers together.
   • To connect with a Crossover cable, simply plug an end of the cable into the Ethernet Port of each computer.
   • To connect with a Hub or Switch, use two strait through cables to connect each computer to the switch or hub.
   • See “Things you will need” section for more information on “Strait Through” -vs- “Cross-Over” Cables.
3. Configure the computers for networking. Go to internet options (this varies depending on the Operating System), and go to the dialog box that lets you change the TCP/IP protocol. Change the radio buttons from “Obtain from DHCP server automatically” to “Use the following IP address:”.
   • Give each computer a different address from the host range. Do not use the network address or the broadcast address.
   • Leave the “Default Gateway” and “DNS server” fields blank.
   • For the subnet mask, use the following:

     Class “A” Networks
     When the first number is 0 to 127
     The Mask is - 255.0.0.0

     Class “B” Networks
     When the first number is 128 to 191
     The Mask is - 255.255.0.0

     Class “C” Networks
     When the first number is 192 to 223
     The Mask is - 255.255.255.0

     IPv4 originally used the first number (ex. 192) to determine which part of the address is network and which part is host based on the address class. However, the advent of subnetting and nonclassful networking made it necessary to provide a mask because other ways of dividing the address into network and host portions are now possible.(More information in the Important Notes section.)

4. Verify connectivity. The simplest way to do this is with Ping. Bring up MS-DOS or the equivalent on other OS’s, (In Windows open the command prompt which is located in the Start Menu - Accessories - Command Prompt) and type in: “ping [insert IP address of the other computer here] (ex. 192.168.1.1). If you cannot reach the other computers address, read over the steps again or contact a professional.

Dynamic Host Configuration Protocol (DHCP) is the configuration of your Internet Protocol (IP) address, subnet mask, DNS servers, domain name suffix and about 200 other possible options to let your computer communicate with a network automatically via a server or router. It sounds complicated, but once set up, it can make connecting to a network much easier.

1. Log into Windows XP with administrator rights. This makes setting up the network for you, and other users, easier as you can make all the necessary changes to settings.
2. Look for the Network Neighborhood or My Network Places icon in your desktop. If it is not there, try your Start Menu.
3. Right-click the Network Neighborhood/My Network Places icon. A drop-down menu will appear.
4. Choose the “Properties” option, generally found at the bottom of the menu.
5. Look for an icon named “Local Area Connection”. The icon looks like a pair of computer connected by a link. Double-click this icon.
6. Click the “General” tab, if it is not already selected. You will see a list of protocols to choose form.
7. Scroll down and choose Internet Protocol (TCP/IP), and then click the button that is labeled “Properties”.
8. Again, click the “General” tab, it it is not alreay selected. You will see two choices:
   1. “Obtain an IP address Automatically”
   2. “Use the following IP address…”
9. Choose option 1.
10. You have effectively configured DHCP for your PC. When your computer obtains the IP address, it will also obtain DNS server information automatically. This is provided by your dhcp server.

If your printer has a built-in ethernet adaptor, adding your printer to your network is a snap. These instructions are appropriate for most HP printers with an ethernet adaptor. The instructions will differ slightly for those with an external print server. Here’s what you do:

1. If you use MAC address filtering on your wireless network, you will need to add your printer’s MAC address to your router configuration. If you don’t use MAC address filtering for your wireless network, you can skip to Step 4.
2. To get your printer’s MAC address, first print your printer’s configuration settings.
3. On the display menu, push the Menu button until you get to the Information Menu. Click the Item button to the right until you get to the Printer Configuration display. Hit Select.
4. Look for the printer’s hardware address on the configuration printout.
5. Using your web browser, login to your router’s configuration. Add your printer’s MAC address to the MAC address filtering area.
6. Perform a cold reset of your printer.
7. Remove the LAN cable.
8. Press & hold the Online/Go button while turning it on & continue to hold it until the display shows Cold Reset, then release it, wait for Ready, then turn it off again.
9. Connect the LAN cable and turn the printer back on.
10. Wait 2 minutes for your network to find your printer.
11. Print a printer configuration page (see Step 2). Note the IP Address for the printer.
12. Make sure your printer?s IP address is something other than 164.XX.XX.XX. Most routers use an IP address that looks like 192.168.XX.XX.
13. Install and run HP’s network printing wizard:
14. http://h20000.www2.hp.com/bizsupport/TechSupport/DriverDownload.jsp?pnameOID=19656&locale=en_US&taskId=135&prodTypeId=18972&prodSeriesId=27908&swEnvOID=228
15. Follow the screen prompts and either input your printer?s IP address or MAC address.