Windows 7 : Troubleshooting Network Printers (part 4) - Troubleshooting Network Problems

Troubleshooting Network Problems

Problems connecting to shared printers can be caused by several different factors:

• The client can't find the server because of a name resolution problem.

• A firewall is preventing the client from connecting to the server.

• The server is rejecting the user's credentials.

In most cases, printer troubleshooting begins when a user calls to complain. Therefore, you typically begin troubleshooting from the client computer. Depending on the nature of the problem, you might also have to log on to the print server. The following sections describe the troubleshooting process, assuming that the client and server are domain members.

How to Troubleshoot Printer Sharing from the Client

Perform these steps to troubleshoot problems connecting to shared printers:

1. Stop the Offline Files service if it is started. If the Offline Files service is running, Windows might report that it can connect to a remote server even though the server is not available. You can stop the Offline Files service from the Services console or by running the command net stop cscservice from an administrative command prompt.

2. If you are connecting using File And Printer Sharing, instead of using Internet Printing Protocol (IPP) or Line Printer Daemon/Line Printer Remote (LPD/LPR), attempt to establish a NetBIOS connection manually. Open a command prompt and issue the command net view \\server. If the connection succeeds, it tells you the exact name of the shared printer, and you know there is not a network or firewall connectivity problem. If you receive an "Access is denied" message when attempting to connect to the printer, the user account lacks sufficient permissions to access the shared printer. Depending on the server configuration, you might be able to identify authentication problems by viewing the Security event log on the server.
   

3. If you stopped the Offline Files service in step 1, restart it now using the Services console or by running the command net start cscservice from an administrative command prompt.

4. Verify that you can resolve the server's name. If you cannot resolve the server's name because the Domain Name System (DNS) server is offline, you can work around the name resolution problem by connecting using the server's Internet Protocol (IP) address rather than the server's host name. For example, instead of connecting to \\servername\printer, you might connect to \\10.1.42.22\printer.

5. If you are connecting using File And Printer Sharing, use PortQry to test whether the client can connect to TCP port 445 or TCP port 139 on the server. If you are connecting with IPP, test whether the client can connect to TCP port 80 on the server.

How to Troubleshoot Printer Sharing from the Server

If you are sharing a printer from a computer running Windows 7, you can troubleshoot it by performing these steps:

1. Verify that you can print from the print server. If you cannot print, the problem is not related to printer sharing. Instead, you should troubleshoot the problem as a local printer problem. Start by using the Printer Troubleshooter. Clear the print queue and then attempt to print again. If you are still unable to print, reinstall the printer with the latest driver.

2. Verify that the folder or printer is shared. To do this, right-click the printer and then click Printer Properties. Then, click the Sharing tab, and verify that Share This Printer is selected.

3. Though the Printer Troubleshooter already should have verified this, you can verify manually that the Server and Print Spooler services are running. To do this, click Start, right-click Computer, and then click Manage. Under Services And Applications, select the Services node. Verify that the Server and Print Spooler services are started and the Startup Type is set to Automatic.

4. Verify that users have the necessary permission to access the resources. To do this, right-click the printer and then click Printer Properties. In the printer properties dialog box, click the Security tab. Verify that the user account is a member of a group that appears on the list and that the Print Allow check box is selected. If the account is not on the list, add it to the list and grant the Print Allow permission.

5. Check the Windows Firewall exceptions to verify that they are configured properly by performing the following steps:

   1. Click Start and then click Control Panel.

   2. Click System And Security and then click Windows Firewall.

   3. In the Windows Firewall dialog box, note the Network Location. Click Allow A Program Or Feature Through Windows Firewall.

   4. On the Allowed Programs window, determine whether the File And Printer Sharing check box is selected. If it is not selected, click Change Settings and select it for the current network location. If it is selected, verify that no other firewall rule is blocking File And Printer Sharing. Click OK.

Firewall Configuration

Firewalls, including Windows Firewall, selectively block network traffic that has not been allowed explicitly. Most firewalls block incoming connections (connections sent from a client to a server) by default, and allow all outgoing connections (connections sent from a server to a client). Therefore, if printer sharing has not been allowed explicitly on a print server, clients are unable to connect. If clients are unable to connect to a print server, you should check the firewall configuration on the print server. If the client and server are not on the same local area network (LAN), you must also check the configuration of any firewalls that might block traffic between the client and server.

How you configure the firewall depends on the network protocol used to connect to the print server:

• File And Printer Sharing This type of printer connection uses a Universal Naming Convention (UNC) path such as \\servername\printer or \\192.168.1.10\printer. If the File And Printer Sharing exception is enabled on the print server, as shown in Figure 4 Windows Firewall allows connections to the shared printer. This firewall exception is enabled automatically when you share a printer; however, administrators might have removed the exception either manually or by using Group Policy.

• Internet Printing Protocol (IPP) This type of printer connection uses a Universal Resource Locator (URL) path such as http://server/printers/printer/.printer. Windows Vista and Windows 7 can only act as an IPP client; they cannot share a printer using IPP. However, Windows XP, Windows Server 2003, and Windows Server 2008 can share printers using IPP. For HTTP connections, the server must allow incoming connections using TCP port 80. For HTTPS connections, the server must allow incoming connections using TCP port 443.

Figure 4. Verify that the File And Printer Sharing firewall exception is enabled.

PRACTICE: Troubleshooting Printer Problems

In this practice, you troubleshoot two different printer problems.

EXERCISE 1 Troubleshooting Printer Sharing

In this exercise, you troubleshoot a client computer that cannot print to a print server.

1. Connect a printer to your domain controller, DC1. Alternatively, you can connect a printer to any computer running Windows 7 or Windows Server 2008 R2 in your test environment. The computer should not be part of a production environment, however. If you do not have a printer, you can install a printer driver manually for a printer that is not connected.

2. Share the printer from DC1 by following these steps:

   1. On DC1, click Start and then click Devices And Printers.

   2. Right-click the printer and then click Printer Properties.

   3. On the Sharing tab, select the Share This Printer check box and the List In The Directory check box. Click OK.

3. Connect to the printer from CLIENT1 by following these steps:

   1. On CLIENT1, click Start and then click Devices And Printers.

   2. Click Add A Printer.

   The Add Printer wizard appears.

   1. On the What Type Of Printer Do You Want To Install? page, click Add A Network, Wireless, Or Bluetooth Printer.

   2. On the next page, click the printer you shared from DC1, and then click Next.

   3. On the You've Successfully Added page, click Next.

   4. Click Print A Test Page to verify that the printer is installed successfully. Then, click Finish.

4. On DC1, verify that the page prints successfully. If you do not have a physical printer, double-click the printer from the Devices And Printers page and verify that a document is in the queue.

5. Right-click the script Ch3-lesson1-ex1-script1.cmd and then click Run As Administrator to introduce a printer problem that you will solve in the steps that follow.

6. From CLIENT1, attempt to print again. You can print by double-clicking the printer from the Devices And Printers page, clicking Customize Your Printer, and then clicking Print Test Page from the General tab of the Printer Properties dialog box. Notice that the document is added to the print queue on CLIENT1, but it does not appear on the print queue in DC1. This indicates that the connection between the client and server is unavailable.

7. From CLIENT1, troubleshoot the network connectivity problem by performing the following steps:

   1. Open an administrative command prompt and attempt to ping DC1 from CLIENT1. You should be able to ping DC1 successfully, indicating that CLIENT1 and DC1 can communicate.

   2. While still at the command prompt on CLIENT1, attempt to stop the Offline Files service by running the command net stop cscservice. Make note of whether the service was already stopped or whether Windows 7 had to stop it.

   3. While still at the command prompt on CLIENT1, attempt to establish a NetBIOS connection by running the command net view \\dc1. Notice that the connection attempt fails with the message "The network name cannot be found." This indicates that CLIENT1 cannot connect to the Server service on DC1. You know the computer must be online and connected to the network because the previous ping attempt succeeded; therefore, you can conclude that the Server service is unavailable.

   4. If you had to stop the Offline Files service in step b, restart it by running the command net start cscservice at the administrative command prompt on CLIENT1.

   5. Verify that the Server service is running. To do this, on DC1, click Start, right-click Computer, and then click Manage. In the Computer Management console, select the Services And Applications\Services node. Scroll to the Server service and verify that it is running and that the Startup Type is set to Automatic.

   6. Verify that File And Printer Sharing is allowed in Windows Firewall. Click Start and then click Control Panel. Click System And Security, and then click Allow A Program Through Windows Firewall. Verify that File And Printer Sharing is selected.

   7. While still in the Windows Firewall Allowed Programs window, examine other firewall rules, and notice the rule named Block File And Printer Sharing. As indicated by the name, this firewall rule might be blocking the connection attempt. Click Change Settings, and then clear the Block File And Printer Sharing check box. Click OK.

8. On DC1, switch to the printer window. Notice that the document you printed earlier is now in the queue or is already printing, indicating that you solved the problem.

9. Finally, right-click the script Ch3-lesson1-ex1-script2.cmd and then click Run As Administrator to remove the firewall rule that the first script added. Then, remove the printer that you added in step 1 of this exercise.

EXERCISE 2 Troubleshooting a Local Printer

In this exercise, you install a printer and troubleshoot problems printing locally.

1. Connect a printer to your computer running Windows 7, CLIENT1. Alternatively, you can connect a printer to any computer running Windows 7 or Windows Server 2008 R2 in your test environment. The computer should not be part of a production environment, however. If you do not have a printer, you can install a printer driver manually for a printer that is not connected. When you install the printer, choose to print a test page and verify that the printer functions correctly.

2. Right-click the script Ch3-lesson1-ex2-script1.cmd and then click Run As Administrator to introduce a printer problem that you will solve in the steps that follow.

3. From CLIENT1, open Windows Internet Explorer. Then, press Ctrl+P to print the current Web page. Notice that you receive an error indicating that you do not have a printer installed. Click OK, and then click Cancel.

4. From CLIENT1, troubleshoot the local printer problem by performing the following steps:

   1. Verify that your printer is still installed. Click Start, and then click Devices And Printers. Notice that no printers are listed. This can happen if either all printers were deleted or if the Print Spooler service is not running.

   2. Verify that the Print Spooler service is running. Click Start, right-click Computer, and then click Manage. In the Computer Management console, select the Services And Applications\Services node. Scroll to the Print Spooler service and notice that it does not have a Status of Started. Right-click the service and then click Start.

5. Return to Internet Explorer and press Ctrl+P again to print the current Web page. Click Print to verify that you can print successfully.

6. Finally, remove the printer that you added in step 1 of this exercise.