Troubleshooting network printing

By Lisa Phifer

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You've created a home network (see "Adding a second computer to your home network").  And you even connected a network printer (see "How to share printers in your home network"). Everything was going smoothly, until Junior connected his laptop. He can't find your network printer, much less print his homework. This article explains how to figure out what might be wrong and -- better yet -- how to fix it.

If you would rather watch than read along, check out our series of short video tutorials:

• Basic setup of a networked printer
• Searching for an existing printer
• Using printer property sheets

Locate your print server

You can share a printer on your home network in several ways, so start by identifying the device that’s behaving as your network print server:

a) Is your printer connected by USB or parallel cable to a desktop computer?  If so, we’ll debug that desktop’s print server using the Windows Control Panel.
b) Is your printer connected by USB or parallel cable to your broadband gateway?  If so, we’ll debug that gateway’s print server using the gateway’s Web interface.
c) Is your printer connected by Wi-Fi or Ethernet to your home network?  If so, we’ll debug that embedded print server using your printer’s status monitor – typically reached from a Web browser or a program installed on a nearby PC.
d) Is your printer connected to an external device that is connected to your network?  If so, we’ll debug that dedicated print server through its Web interface

(fig 1)Find your print server

Get physical

Take a few minutes to check and double-check those physical cable connections.  Is the printer’s USB or parallel cable firmly inserted?  Has the print server’s Ethernet cable been yanked loose or damaged by a hungry vacuum cleaner?  Are both devices plugged in and powered on?  These checks may seem obvious, but all too often we start looking for a network or software problem when the culprit is plain old physical disconnection – easily found, and just as easily resolved.

Link the laptop

After ruling out physical disconnection, confirm that Junior’s laptop is linked to your home network.  If you can’t surf the web from the laptop, the problem is almost certainly the laptop’s connection.  If the laptop can use the Internet but not your printer, your home network may be at fault.  Either way, you’ll need the IP address assigned to that laptop.

On a laptop running Windows 2000, XP or Vista, use the Windows Start menu to invoke Run and type “cmd” in the resulting pop-up window.  From here on, we’ll refer to this as “opening a new command window.”  Get to know this command window, because it will be your best friend throughout the trouble-shooting process.

In the command window, type “ipconfig” and jot down the numbers that appear after “IP Address” – for example, 10.0.1.49.  If the laptop has more than one kind of connection (for example, Ethernet and Wi-Fi) then look for the adapter actually connected to your home network.

• If that adapter is not even listed in ipconfig results, then the adapter is disabled.
• If that adapter is listed but says “media state disconnected,” then the adapter is enabled but not actually connected to your wireless network.
• If that adapter is listed, but the IP address starts with 0 or 169, then the laptop was unable to get an IP address from your broadband gateway.
• Otherwise, ping the listed Default Gateway (for example, “ping 10.0.1.1”).  If the result is “Request timed out” then you have a routing or personal firewall problem.

For advice on how to correct these basic connection issues, see "Adding a second computer to your home network."  If using Wi-Fi, also see “Securing your wireless home network” to diagnose security mismatches.  Don’t worry about printing until that laptop is actively connected to your home network, and you know its current IP address.

(fig 2)Check your laptop’s network connection

Follow the route

Next, confirm that the laptop can traverse your home network to reach your print server.  To complete this step, you’ll need to find the print server’s current IP address.

a) For a desktop print server, go to that desktop PC and repeat the above steps to find the current IP address of that Windows desktop.
b) For a gateway print server, simply jot down the Default Gateway IP address displayed by the laptop above.
c) For an embedded print server, look for the IP address displayed in your printer’s status monitor program (for example, see Figure 3).
d) Otherwise, consult your dedicated print server’s manual to find its default IP address, or check your gateway’s DHCP list for the IP address now assigned to the server.  For example, a gateway that assigns addresses in the range 10.0.1.50 through 100 may well assign 10.0.1.50 to your print server.  You’ll know you have the right address when you can use that IP to open a browser to your print server’s Web interface.

(fig 3) Locate the embedded print server’s IP address

Once you know the printer server’s IP address, open a command window on the laptop and ping the printer server (in Figure 3, we’d ping 10.0.0.9).  If the result is “Request timed out” then reboot or power the print server off/on and try again.  Warning: the server’s IP address may change after reboot.

In most home networks, the print server and laptop share a subnet. That means they have identical subnet masks and default gateways, but unique IP addresses in a shared range.  Compare your laptop’s “ipconfig” output with your print server’s settings.  In Figure 1, our laptop used IP address 10.0.1.49, subnet 255.255.255.0, and gateway 10.0.1.1.  Typically, our print server would use the same subnet and gateway, with an IP address 10.0.1.x, where x is neither 49 nor 1.  Oddities here, like different subnet masks or duplicate IP addresses, can cause routing problems.  If you spot anything suspicious, see "Adding a second computer to your home network" and your server’s manual.  For example, your server may have mysteriously reverted to factory defaults and must be reconfigured to use an IP address within your subnet.

In home networks with multiple gateways, the laptop and server may reside in different subnets.  For example, if you combined an existing broadband gateway with a new Wi-Fi access point, that old gateway might need to be told how to forward print requests from Wi-Fi laptops to an Ethernet print server.  Figure 4 illustrates how to do this on a Linksys gateway by designating the print server as a “DMZ host.”  In this example, we can “ping 192.168.15.1” from the laptop and end up reaching the print server at 10.0.0.9.  Although your own network layout and gateway may differ, your goal is the same as shown here: forward incoming requests – at least print messages – to your print server.

(fig 4)Sending print requests through a broadband router

After all of this, if you still cannot ping your print server, there is at least a small chance that the server malfunctioned due to a power spike, overheating or software corruption.  On an embedded or dedicated print server, look for a button that resets the device to factory defaults. Gateway and desktop print servers rarely malfunction to this degree without causing much bigger problems. For example, a desktop print server that cannot reach either the laptop or the Internet is experiencing a broader network failure that goes beyond what we can hope to fix in this article.

Search for the printer

Once you can ping the server from the laptop but still cannot print, you have narrowed the problem to network printing.  To print, the laptop must find and talk to the printer.

In "How to share printers in your home network," we explained that print servers and clients may speak several different languages (network printing protocols).  In Windows networks, print servers and clients usually converse using Server Message Block (SMB).  In a mixed network, print servers and clients may speak the Internet Printing Protocol (IPP) or the Line Printer Remote (LPR) protocol.  This impacts exactly what the client calls the printer and how it must submit documents to be printed.  However, we generally combine the print server’s name or IP address with the shared printer’s name.  For example, the HP printer connected to the print server 10.0.1.49 might be called \\10.0.1.49\HP (using SMB) or http://10.0.1.49/printers/HP/ (using IPP).

Try to open a web browser from the laptop to the printer server (http://SERVER-IP-ADDRESS/printers/ or ipp://SERVER-IP-ADDRESS/).  If the server shares printers in this fashion, it will respond with a Web page that lets you browse and connect the laptop to those printers.  When using a non-Windows print server, consult the server’s manual for hints on how to correctly refer to IPP-based print services and printers.

If IPP does not work or does not apply to your network, use the laptop’s Start menu to open the Printers and Faxes control panel and launch the Add Printer wizard.  When prompted, choose “A network printer or a printer attached to another computer.”  Click Next, then choose “Browse for a printer.”  If any server on your network shares printers via SMB, you will be presented with a list of advertised computers and printers (illustrated in Figure 5).  If you’re lucky, the printer that you want will appear in this list – just select that printer, click Next, and follow instructions to complete setup.

(fig 5)Browsing for a Windows Network printer

If your printer does not appear on this browse list, you can manually add the printer.  Click the Back button on the screen shown in Figure 5, or launch a new Add Printer wizard.  When prompted, choose “Connect to this printer” and type:
\\SERVER-IP-ADDRESS-OR-NAME\PRINTER-NAME
For example, the printer discovered in Figure 5 could have been added manually as either \\10.0.1.49\HP or \\INS\HP (where INS is the desktop print server’s name).

In all of these cases, the laptop’s operating system will try to install a driver for the new printer, adding an icon to the laptop’s Printers and Faxes control panel.  If all goes well, you will print a test page and find that Junior’s problem has been solved.  If you do not succeed at first, try deleting and re-adding the printer to the laptop, particularly if printer setup was interrupted mid-stream during Junior’s first attempt to print.

Look under the hood

If you reach this point without resolving your problem, it’s time to drill deeper.  Although there are many potential culprits, you have eliminated all of the basics.  What else might be wrong?  Consider the following possibilities:

• Is Junior’s laptop connection configured to support network printing?  On a Windows laptop, open the Network Connections control panel, choose the connection to your home network, and open its Properties panel.  The box next to “Client for Microsoft Networks” must be checked.  If you change this setting, disable and re-enable the connection before browsing for the printer again.
• Is Junior’s laptop permitted to access the shared printer?  Sharing must be enabled on the print server in general and for this printer in particular.  If no network clients can print, double-check your server and printer settings against the instructions found in "How to share printers in your home network."  If Junior is the only client without access to a Windows print server, check the Security tab on that server’s Printer Properties panel (Figure 6) to make sure that Junior is allowed to print.
• Is Junior’s laptop compatible with the drivers offered by the shared printer?  On a Windows print server, check the Sharing tab on the Printer Properties panel (Figure 6), clicking on Additional Drivers.  Make sure the laptop’s operating system is checked, or consult your non-Windows print server or printer manual for a list of supported client systems and where to obtain additional drivers for them.

(fig 6)Checking a printer’s Sharing and Security Properties

• Should Junior’s laptop be communicating with the print server in a different way?  Some embedded print servers are reached by adding a local (not network) printer, bound to a specified TCP/IP port (see Figure 7).  Consult your print server manual for instructions, including the required port number and printer protocol, then use those values to configure a new “local” printer on Junior’s laptop.

(fig 7)Adding a “local” printer reached via TCP/IP

Follow the clues

Although network-printing problems can feel a bit mysterious, following a methodical process can help to spot potential problems and isolate the system likely to be at fault. Remember, when using a Windows print server, shared printer configuration and status can always be viewed from the Printers and Faxes Control Panel.  A Print Server Properties page can also be reached from that Control Panel’s File menu.  Otherwise, when using a standalone, embedded or gateway print server, use the server’s console program or Web interface to examine settings, status and history/error logs.  If all else fails, consult your laptop OS, print server and printer vendor’s knowledge bases or user forums, looking for that secret incantation needed to get Junior’s homework printed.