Microsoft Windows XP Professional Resource Kit 2003
ISBN: N/A
EAN: N/A
EAN: N/A
Year: 2005
Pages: 338
Pages: 338
The following sections describe common troubleshooting issues with the Network Connections feature in remote office environments as well as the relevant troubleshooting tools provided with Windows XP Professional.
There are many tools within Windows XP Professional that allow you to monitor modem or Point-to-Point Protocol (PPP) activity and diagnose network and dial-up connections, including:
PPP logging
Modem logging
Modem diagnostics
Netdiag
Device Manager
PPP logging records the series of programming functions and PPP control messages during a PPP connection. The PPP logs are a valuable source of information when you are troubleshooting the failure of a PPP connection.
| Note | Routing and Remote Access service must be restarted for changes in logging settings to take effect. |
To enable PPP logging on the client that is initiating the connection, use the Netsh command line tool. The syntax for the command is:
netsh set ras tracing * enabled
Conversely, if you want to stop PPP logging, the command syntax is:
netsh set ras tracing * disabled
By using Phone and Modem Options in Control Panel, you can record a log of commands as they are sent to your modem by communication programs or the operating system. On Windows XP Professional, logging is always turned on and the log is overwritten at the beginning of every session unless you select the Append to Log check box.
| Note | Commands sent to the modem are captured in the file systemroot\ModemLog_Model.txt. In this file path, Model is the name of the modem as it appears in the list of installed modems on the Modems tab of Phone and Modem Options. |
When you query a modem, Windows XP Professional runs the commands and displays the results, as shown in Table 23-6.You can verify whether your modem is working properly by using the diagnostic queries that are available by means of Phone and Modem Options in Control Panel.
| Command | Response |
|---|---|
| ATQ0V1E0 | Initializes the query. |
| AT+GMM | Identifies the modem model (ITU V.250 recommendation is not supported by all modems). |
| AT+FCLASS= ? | Identifies the fax classes supported by the modem, if any. |
| AT#CLS=? | Shows whether the modem supports the Rockwell voice command set. |
| ATIn | Displays manufacturer s information for n = 1 through 7. This provides information such as the port speed, the result of a checksum test, and the model information. Check the manufacturer s documentation for the expected results. |
Device Manager provides information about how the hardware on your computer is installed and configured. It can help you determine the source of resource conflicts and the status of COM ports. You can also use Device Manager to check the status of your hardware and update device drivers, such as modem drivers, on your computer.
To open Device Manager
Right-click My Computer.
Click Manage.
In Computer Management window, select Device Manager in the console tree.
The following sections describe common local area related problems that you might encounter, and possible causes and solutions for them.
There are two possible causes for the lack of response when using a LAN connection:
There might be problems with your network adapter. Check the appearance of the local area connection icon in the Network Connections folder. Depending on the status of the local area connection, the icon appears in different ways. Use Device Manager to verify that your network adapter is working correctly.
The LAN cable might not be plugged into the network adapter. If this is the case, a status icon is displayed in the taskbar. Check to make sure the LAN cable is inserted into the network adapter.
The following sections describe common remote access related problems that you might encounter, and possible causes and solutions for them.
The modem is not connected properly or is turned off. Verify that the modem is connected properly to the correct port on your computer. If the modem is external, verify that the power is on.
The modem cabling is faulty. Do not use the 9-to-25-pin converters that are included with most mouse hardware because some of them do not carry modem signals. To be safe, use a converter made especially for this purpose.
You dialed the wrong number, or you dialed the correct number but forgot to dial an external line-access number, such as 9. Verify that the number is correct as dialed.
The modem is incompatible. If you have access to another computer with an Internet connection, check the list of compatible modems in the Hardware Compatibility List link on the Web Resources page at http://www.microsoft.com/windows/reskits/webresources
You do not have a valid user account, or you do not have remote access permission. Verify that your user account has been established, and that you have remote access permission.
The telephone line does not accommodate your modem speed. Select a lower bits-per-second (bps) rate or find a direct line.
The line you are trying to use is digital. Most modems work only with analog phone lines. Verify that you have analog phone lines installed or, if you have digital phone lines installed, verify that the servers and clients have digital modems.
Your modem cannot negotiate with the modem of the server. Try using the same type of modem as the server.
The remote access server is not running. Verify that the remote access service is not running. The administrator needs to carefully check the error and audit logs to see why the service stopped. After the problem is fixed, restart the service. If the service is running, the administrator needs to check whether other remote access clients can connect properly. If other clients can connect, the problem might be specific to your workstation.
The line you are dialing is affecting the speed. If you can connect to your remote access server by using more than one number, try another number and see if the speed improves.
At higher data rates, your modem is incompatible with the modem of the server. Select a lower bps rate.
The modem appears to have a problem connecting. If there is a lot of static on the phone line, this might be preventing the modem from connecting at a higher data rate. Select a lower bps rate.
The modem and telephone line are not operating correctly. This might be the result of dropped sessions caused by excessive static on the telephone line. Although the symptoms might be different than the previous problem, the cause might be the same. You can use modem diagnostics to confirm correct modem operation.
Your modem software needs to be updated. Check with your modem manufacturer for modem software updates.
There is some kind of switching equipment between the client and server that prevents the two modems from negotiating at a higher data rate. Adjust the speed of your modem to a lower data rate.
The quality of your line is insufficient. Contact your telephone company to verify the quality of your line.
The remote access server is not running properly. Try connecting to the same server from another workstation. If other workstations are having the same problem, there might be problems with server applications or hardware. If other clients don t have the same difficulty, the problem could be specific to your workstation.
The remote access server is not running. This might be caused by the modem s tendency to connect at a lower data rate than specified. Verify that the server is running.
The remote access server disconnected you because of inactivity. Try calling again.
Call waiting is disrupting your connection. Verify that the phone has call waiting. If so, disable call waiting, and then try calling again.
Someone picked up the phone. Picking up the phone automatically disconnects you. Try calling again.
Your modem cable is disconnected. Verify that the modem cable is connected properly.
Your modem software needs to be updated. Check with your modem manufacturer for modem software updates.
Your modem settings need to be changed because of a remote access server change. Verify the modem settings.
The remote access server is not running. Verify that the server is running.
Your modem cannot negotiate correctly with the modem of the remote access server. The serial port of the computer cannot match the speed you have selected. Try to connect at a lower initial port speed.
Your modem software needs to be updated. Check with your modem manufacturer for modem software updates.
The external modem is turned off. Verify that the external modem is turned on. If the external modem is turned off, turn it on and redial.
Your modem is not functioning properly. Start modem logging to test the connection.
Your cable is incompatible. If your modem communicates by using Hyper Terminal, but not through Network Connections, the cable that attaches your modem to the computer is probably incompatible. You need to install a compatible cable.
The folder might need to be refreshed. Press F5 to refresh the folder.
The serial ports are conflicting. COM1 and COM3 share interrupt request (IRQ) 4. COM2 and COM4 share IRQ 3. To avoid such serial communications problems, do not use COM1 and COM3 simultaneously, or COM2 and COM4 simultaneously. For example, avoid using Network Connections on COM1 and Terminal on COM3.
This rule applies if you are using a serial mouse in addition to other serial communications programs such as Network Connections. The rule does not apply if you are using an intelligent serial adapter, such as a DigiBoard serial adapter.
The line is busy. Try calling later.
A poor line condition (for example, too much static) interrupted your connection. Wait a few minutes, and then try dialing again.
Your ISDN switching facility is busy. Try again later.
Your phone number is not configured correctly. In some cases, each B channel on an ISDN line has its own number, although in other cases both B channels share a single number. Contact your telephone company to determine how many numbers your ISDN line has.
If you are located in the United States or Canada and using ISDN, your Service Profile Identifier (SPID) is configured incorrectly. The SPID normally consists of the phone number with additional digits added to the beginning, the end, or both. The SPID helps the switch understand what type of equipment is attached to the line and routes calls to appropriate devices on the line. If an ISDN channel requires a SPID, but it is not entered correctly, then the device cannot place or accept calls. Verify that the SPID is entered correctly.
You did not enable line-type negotiation, or a connection cannot be made with the line type you selected. Enable line-type negotiation.
There is a problem with the hardware. Verify that the ISDN adapters are installed and configured correctly.
Your DigiBoard adapter is too old. If you do not have the latest PCIMAC-ISA DigiBoard adapter, serial number A14308 or greater, contact DigiBoard for a replacement.
The remote server did not answer because it is turned off or the modem is not connected. Contact that server s system administrator.
The dial-up packet assembler/disassembler (PAD) is configured with the wrong X.3 parameters or serial settings. If the remote access server is running and you cannot connect to it directly by using an X.25 smart card or an external PAD, modify the dial-up PAD X.3 parameters or serial settings. If they are available, obtain the correct settings.
New Pad.inf entries are incorrect. Check other Pad.inf entries for direct connections and external PADs, and view the comments that appear with them. You might need a line analyzer or a terminal program to see the response for the PAD.
Your modem is incompatible. If the modem that connects to a dial-up PAD connects at a lower speed than it should, replace the modem with a compatible one.
The leased line for the remote access server is congested. This could be caused by congestion on the leased line for the remote access server. Typically, in such an instance, a connection has been established, but the network drives are disconnecting. As a result, you might be dropping sessions or getting network errors.
For example, four clients connecting at 9,600 bps (through dial-up PADs) require a 38,400-bps (four times 9,600) leased line on the server. If the leased line does not have adequate bandwidth, it can cause timeouts and degrade performance for connected clients. This is most likely the case if all bandwidth is dedicated to Routing and Remote Access.
Keeping all of this in mind, verify that the speed of the leased line can support all the COM ports at all speeds clients use to dial in.
TCP/IP connectivity problems are keeping you from connecting to the PPTP server. You can use the ipconfig and ping commands to verify the reachability of the server. Keep in mind that ping will typically fail to a VPN server because of packet filtering at the server.
A legacy Winsock Proxy client, used in Proxy Server 2.0, is active. The Winsock Proxy service requires a protocol definition to identify valid network protocols when access control is enabled. The WinSock Proxy service uses the defined protocols to determine which Windows Sockets applications can be used to access the Internet. A VPN connection cannot operate with an active Winsock Proxy client. Winsock Proxy immediately redirects packets to the proxy server before they can be processed by a virtual private network connection for encapsulation. Disable the Winsock Proxy client. One alternative is to upgrade Proxy Server 2.0 to Microsoft ISA Server 2000, allowing you to run the computer as an ISA Server Firewall client.
You do not have the appropriate connection and domain permissions on the remote access server. Obtain appropriate permissions.
If you are using TCP/IP, you do not have a unique public IP address. Obtain an authorized public IP address.
Name resolution problems are keeping you from resolving names to IP addresses. Specify fully qualified domain names or IP addresses in your connection.
You cannot connect to the PPTP-based VPN server with your DSL modem. Configure the DSL modem to pass TCP port 1723 and IP protocol 47 (most cannot by default). This must occur before a PPTP connection can be established. Some DSL modems refer to this as PPTP passthrough.
You cannot connect to the L2TP-based VPN server with your DSL modem. Configure the DSL modem to pass UDP port 500 and IP protocol 50 (most cannot by default). This must occur before an IPSec SA can be established.
The server does not support Link Control Protocol (LCP) extensions. If you cannot connect to a server by using PPP, or the remote computer terminates your connection, the server might not support LCP extensions.
IP header compression is keeping TCP/IP tools from running. If you successfully connect to a remote server by using PPP, but TCP/IP tools do not work, the problem might be IP header compression.
To disable LCP extensions
In Network Connections, click the dial-up or VPN connection you want to configure.
Under Network Tasks, click Change settings of this connection.
On the Networking tab, click Settings, and then clear the Enable LCP extensions check box.
To disable IP header compression
In Network Connections, click the dial-up connection you want to configure.
Under Network Tasks, click Change settings of this connection.
On the Networking tab, click Internet Protocol (TCP/IP), and then click Properties.
Click Advanced, and then clear the Use the IP Header Compression check box.
The following sections describe common Internet access related problems that you might encounter, and possible causes and solutions for them.
The wrong network adapter is shared. An ICS host computer needs two connections. One connection, typically a network adapter, connects to the computers on the home (or small office) network and the other connection connects the home network to the Internet. Ensure that ICS is enabled on the connection that connects your home network to the Internet.
TCP/IP is not installed on home network computers. By default, the TCP/IP protocol is installed on computers running Windows XP Professional and Windows XP Home Edition, Windows 2000, Windows Me, Windows 98, and Windows NT 4.0. If users on your home network are running operating systems other than these, verify that TCP/IP is installed on their computers.
Users on your home network fail reach the Internet. TCP/IP is incorrectly configured on home network computers. Verify that the following TCP/IP settings are established on home network local area connections:
IP address. Obtain an IP address automatically (by using DHCP).
DNS server. Obtain DNS server address automatically.
Default gateways. None specified.
For computers running Windows 95, Windows 98, or Windows NT 4.0, you can find the TCP/IP settings in Network Control Panel.
Internet Connection Sharing is not started. Use the Services and Applications section of the Computer Management console tree to verify that the Internet Connection Sharing service is started. If stopped appears as the service status, click Start and OK to start the service.
The Internet Connection Sharing computer is not properly configured for name resolution. If computers on the remote office network cannot resolve names to IP addresses, you might need to configure the DNS name resolution services on the ICS host computer. Check the name resolution configuration of the ICS host computer by using the ipconfig command.
If your remote office accesses the Internet through an ISP, there are two ways that your ISP can configure name resolution:
Statically assigning name servers.
You must manually configure the TCP/IP protocol with the IP address (or addresses) of the name servers provided by the ISP. If you have statically assigned name servers, you can run the ipconfig command at any time to get the IP addresses of your configured name servers.
Dynamically assigning name servers.
Manual configuration is not required. The IP addresses of the name servers provided by the ISP are dynamically assigned whenever you dial the ISP. If you have dynamically assigned name servers, you must run the ipconfig command after a connection to the ISP has been made.
The protocol used by a game played on the Internet is not translatable. Try running the game application from the ICS computer. If the game works from the ICS computer but not from a computer on the home network, then the game might not be translatable.
Internet users cannot see services on your home network, such as a Web server. Verify that the ICS service, including port numbers and IP addresses, is configured correctly.
Users on your home network cannot reach the Internet sites by using friendly names. This is a DNS resolution problem. Users on your home network must use fully qualified domain names or IP addresses when accessing Internet resources.
For more information about Internet Connection Sharing, see Windows XP Professional Help and Support Center.
The Winsock Proxy client might be preventing your applications from running properly. If you are a mobile user and use your portable computer in your corporate environment, your applications might not be able to locate the resources or servers they need. Disable the Microsoft Winsock Proxy client (WSP Client in Control Panel) when you use the same computer to dial to an ISP or other network.
DNS options might need to be configured. Check with your ISP to see if you need to configure DNS settings for that connection. For example, you might need to specify a preferred or alternate DNS server IP address, rather than letting the DNS server IP address be assigned dynamically.