Using the Debugging Tools Available in Windows Server 2003

Several useful tools are available in Windows Server 2003 for troubleshooting and diagnosing various problems ranging from TCP/IP connection issues to verification and maintenance issues. These tools also make it much easier for IT professionals, allowing IT personnel to focus on business improvement tasks and functions, not on simply running specific tools in the networking environment.

TCP/IP Tools

TCP/IP forms the backbone of communication and transportation in Windows Server 2003. Before you can communicate between machines, TCP/IP must be configured. In Windows Server 2003, Microsoft decided to make TCP/IP install by default during the OS installation and also made it impossible to add or remove TCP/IP through the GUI.

Microsoft also added four new parameters (-R, -S, -4, -6) to some of the TCP/IP utilities in Windows Server 2003 that were not available in previous versions of Windows; these parameters will be discussed next.

If a TCP/IP connection fails, you need to determine the cause or point of failure. Windows Server 2003 includes some dependable and useful tools that can be used to troubleshoot connections and verify connectivity. The tools described in the following eight sections are very useful for debugging TCP/IP connectivity problems.

PING

PING means Packet Internet Groper. It is used to send an Internet Control Message Protocol (ICMP) echo request and echo reply to verify the availability of a local or remote machine. You can think of PING as a utility that sends a message to another machine asking "Are you still there?" By default, in Windows Server 2003, PING sends out four ICMP packages and waits for responses back in one second. However, the number of packages sent or time to wait for responses can be changed through the options available for PING.

Besides verifying the availability of a remote machine, PING can help determine a name resolution problem.

To use PING, go to a command prompt and type PING Targetname, as shown in Figure 34.14. Different parameters can be used with PING. To display them, type PING /? or PING (without parameters).

Figure 34.14. A PING command in a command-prompt window.

The parameters for the PING command are as follows:

-4 Specifies that IPv4 is used to ping. This parameter is not required to identify the target host with an IPv4 address. It is required only to identify the target host by name.

-6 Specifies that IPv6 is used to ping. Just like 4, this parameter is not required to identify the target host with an IPv6 address. It is required only to identify the target host by name.

-a Resolves the IP address to the hostname. The hostname of the target machine is displayed if this command is successful.

-f Requests that echo back messages are sent with the Don't Fragment flag in packets. This parameter is available only in IPv4.

-i ttl Increases the timeout on slow connections. The parameter also sets the value of the Time to Live (TTL). The maximum value is 255.

-j HostList Routes packets using the host list, which is a series of IP addresses separated by spaces. The host can be separated by intermediate gateways (loose source route).

-k HostList Similar to j but hosts cannot be separated by intermediate gateways (strict source route).

-l size Specifies the length of packets in bytes. The default is 32. The maximum size is 65,527.

-n count Specifies the number of packets sent. The default is 4.

-r count Specifies the route of outgoing and incoming packets. It is possible to specify a count that is equal to or greater than the number of hops between the source and destination. The count can be between 1 and 9 only.

-R Specifies that the roundtrip path is traced (available on IPv6 only).

-S count Sets the time stamp for the number of hops specified by count. The count must be between 1 and 4.

-S SrcAddr Specifies the source address to use (available on IPv6 only).

-t Specifies that PING should continue sending packets to the destination until interrupted. To stop and display statistics, press Ctrl+Break. To stop and quit PING, press Ctrl+C.

-v TOS Specifies the value of the type of service in the packet sent. The default is zero. TOS is specified as a decimal value between 0 and 255.

-w timeout Specifies the time in milliseconds for packet timeout. If a reply is not received within the timeout, the Request Timed Out error message is displayed. The default timeout is four seconds.

TargetName Specifies the hostname or IP address of the destination to ping.

Note

Some remote hosts may be configured to ignore PING traffic as a method of preventing acknowledgment as a security measure. Therefore, your inability to ping a server may not necessarily mean that the server is not operational, just that the server is not responding for some reason.

Tracert

Tracert is generally used to determine the route or path taken to a destination by sending ICMP packets with varying Time to Live values. Each router the packet meets on the way decreases the value of the TTL by at least one; invariably, the TTL is a hop count. The path is determined by checking the ICMP Time Exceeded messages returned by intermediate routers. Some routers do not return Time Exceeded messages for expired TTL values and are not captured by Tracert. In such cases, asterisks are displayed for that hop.

To display the different parameters that can be used with Tracert, open a command prompt and type tracert (without parameters) to display help or type tracert /?. The parameters associated with Tracert are as follows:

-4 Specifies that tracert.exe can use only IPv4 for the trace.

-6 Specifies that tracert.exe can use only IPv6 for the trace.

-d Prevents resolution of IP addresses of routers to their hostname. This is particularly useful for speeding up results of Tracert.

-h maximumHops Specifies the maximum number of hops to take before reaching the destination. The default is 30 hops.

-j HostList Specifies that packets use the loose source route option. Loose source routing allows successive intermediate destinations to be separated by one or multiple routers. The maximum number of addresses in the host list is nine. This parameter is useful only when tracing IPv4 addresses.

-R Sends packets to a destination in IPv6, using the destination as an intermediate destination and testing reverse route.

-S Specifies the source address to use. This parameter is useful only when tracing IPv6 addresses.

Note

Tracert is a good utility to determine the number of hops and the latency of communications between two points. Even if an organization has an extremely high-speed connection to the Internet, if the Internet is congested or if the route a packet must follow requires forwarding the information between several routers along the way, the performance and ultimately the latency (or delay in response between servers) will cause noticeable communications delays.

Pathping

Pathping is a route tracing tool that combines both features of PING and TRacert commands with some more information that neither of those two commands provides. Pathping is most ideal for a network with routers or multiple routes between the source and destination hosts. The Pathping command sends packets to each router on its way to a destination, and then gets results from each packet returned from the router. Because Pathping computes the loss of packets from each hop, you can easily determine which router is causing a problem in the network.

To display the parameters in Pathping, open a command prompt and type Pathping /?. The parameters for the Pathping command are as follows:

-g Host-list Allows hosts to be separated by intermediate gateways.

-h maximumHops Specifies the maximum number of hops before reaching the target. The default is 30 hops.

-n Specifies that it is not necessary to resolve the address to the hostname.

-p period Specifies the number of seconds to wait between pings. The default is a quarter of a second.

-q Specifies the number of queries to each host along the route. The default is three seconds.

-R Determines whether the hosts along the route support Resource Reservation Setup Protocol. The route supports the Resource Reservation Setup Protocol to allow host computers to reserve bandwidth for data streams. Note that this parameter must be in uppercase.

-T Identifies network devices that do not have Layer 2 priority configured. This parameter must be in uppercase.

Ipconfig

Ipconfig displays all TCP/IP configuration values. It is of particular use on machines running DHCP. It is used to refresh DHCP settings and to determine which TCP/IP configuration values have been assigned by DHCP. If Ipconfig is used without parameters, it displays IP addresses, subnet masks, and gateways for adapters on a machine. The adapters can be physical network adapters or logical adapters such as dial-up connections.

The parameters for Ipconfig are as follows:

-all Displays all TCP/IP configuration values.

/displaydns Displays the contents of the DNS client resolver cache.

/flushdns Resets and flushes the contents of the DNS client resolver cache. This includes entries made dynamically.

/registerdns Sets manual dynamic registration for DNS names and IP addresses configured on a computer. This is particularly useful in troubleshooting DNS name registration or dynamic update problems between a DNS server and client.

/release [Adapter] Sends a DHCP release message to the DHCP server to discard DHCP-configured settings for adapters. This parameter is available only for DHCP-enabled clients. If no adapter is specified, IP address configuration is released for all adapters.

/renew [Adapter] Renews DHCP configuration for all adapters (if an adapter is not specified) and for a specific adapter if the Adapter parameter is included. This parameter is available only for DHCP-enabled clients.

/setclassid Adapter [classID] Configures the DHCP Class ID for a specific adapter. You can configure the DHCP class ID for all adapters by using the wildcard (*) character in place of Adapter.

/showclassid Adapter Displays the DHCP class ID for a specific adapter.

Note

Ipconfig determines the assigned configuration for a system such as the default gateway, DNS servers, local IP address, subnet mask, and the like. When you're debugging network problems, you can use Ipconfig to validate that the proper TCP/IP settings have been set up for a system so that a server properly communicates on the network.

Arp

Arp stands for Address Resolution Protocol. Arp enables the display and modification of the Arp table on a local machine, which matches physical MAC addresses of machines to their corresponding IP addresses. Arp increases the speed of connection by eliminating the need to match MAC addresses with IP addresses for subsequent connections.

The parameters for Arp are as follows:

-a [InetAddr] [-N IfaceAddr] Displays the Arp table for all adapters on a machine. Use Arp -a with the InetAddr (IP address) parameter to display the ARP cache entry for a specific IP address.

-d InetAddr [IfaceAddr] Deletes an entry with a specific IP address (InetAddr). Use the IfaceAddr parameter (IP address assigned to the interface) to delete an entry in a table for a specific interface. Use the wildcard character in place of InetAddr to delete all entries.

-g [InetAddr] [-N IfaceAddr] Similar to the a parameter.

-s InetAddr EtherAddr [IfaceAddr] Adds a static entry to the ARP cache that resolves the IP address (InetAddr) to a physical address (EtherAddr). To add a static ARP cache entry to the table for a specific interface, use the IP address assigned to the interface (IfaceAddr).

Netstat

As its name implies, Netstat (or Network Statistics) is used to display protocol statistics for any active connections, monitor connections to a remote host, and monitor IP addresses or domain names of hosts with established connections.

The parameters for Netstat are as follows:

-a Displays all connections and listening ports by hostname.

-an Similar to the a parameter, but displays connections and listening ports by IP addresses.

-e Displays Ethernet packets and bytes to and from the host.

-n Displays address and port numbers without resolving the address to the hostname.

-o Displays TCP connections and includes the corresponding process ID (PID). Used in combination with a, -n, and p. Not available in previous Windows versions.

-P protocol Displays statistics based on the protocol specified. Protocols that can be specified are TCP, UDP, TCPv6, or UDPv6. It can be used with s to display TCP, UDP, ICMP, IP, TCPv6, UDPv6, ICMPv6, or IPv6.

-s Displays statistics on a protocol-by-protocol basis. Can be used with the p parameter to specify a set of protocols.

-r Displays the route table. Information displayed includes network destination, netmask, gateway, interface, and metric (number of hops).

[Parameter] Interval Displays the information at every interval specified. Interval is a numeral in seconds. Press Ctrl+C to stop the intervals.

NetDiag

The Network Connectivity Tester (NetDiag) tool is a command-line diagnostic tool to test network connectivity, configuration, and security. It's included with the Support Tools on the Windows Server 2003 media. The tool gathers information on and tests network configuration, network drivers, protocols, connectivity, and well-known target accessibility. This is a good tool to use right off the bat if you think there are problems with the network connectivity of a system.

One nice feature of the NetDiag.exe tool is that it does not require parameters, which makes it easy to use. Simple instructions can be given to the administrators that need to execute it, and the bulk of the time can be spent analyzing the results.

Although it doesn't require any parameters, there are several available:

/q Quiet output (errors only).

/v Verbose output.

/l Logs to the NetDiag.log.

/debug Even more verbose output.

/d: DomainName Finds a domain controller in the domain.

/fix Fixes minor problems.

/DCAccountEnum Enumerates domain controller computer accounts.

/test: TestName Runs the specified tests only.

/skip: TestName Skips the specified tests.

When specifying tests to run or to skip, nonskippable tests will still be run.

DCDiag

The Domain Controller Diagnostic (DCDiag) tool analyzes the state of domain controllers and services in an Active Directory forest. It is included with the Support Tools on the Windows Server 2003 media. This is a great general-purpose test tool for checking the health of an Active Directory infrastructure.

Tests include domain controller connectivity, replication errors, permissions, proper roles and connectivity, and other general Active Directory health checks. It can even run nondomain controllerspecific tests, such as whether a server can be promoted to a domain controller (the DcPromo test), or register its records properly in DNS (RegisterInDNS test).

DCDiag is run on domain controllers exclusively, with the exception of the DcPromo and RegisterInDNS tests. When run without any parameters, the tests will be run against the current domain controller. This runs all the key tests and is usually sufficient for most purposes.

The parameters for DCDiag are as follows:

/s:DomainController Uses the domain controller as the home server.

/n:NamingContext Uses the specified naming context (NetBIOS, FQDN, or distinguished name) to test.

/u:Domain\UserName /p:{*Password""} Uses the supplied credentials to run the tool.

/e Tests all domain controllers in the enterprise.

/q Quiet output (errors only).

/v Verbose output.

/I Ignores minor error messages.

/fix Fixes minor problems.

/f:LogFile Logs to the specified log file.

/ferr:ErrorLogFile Logs errors to the specified log file.

/c Comprehensively runs all tests.

/test:TestName Runs the specified tests only.

/skip:TestName Skips the specified tests.

When specifying tests to run or to skip, nonskippable tests will still be run.

Route

Route is particularly useful for troubleshooting incorrect static routes or for adding a route to a route table to temporarily bypass a problem gateway. Static routes can be used in place of implicit routes specified by a default gateway. Use Route to add static routes to forward packets going to a gateway specified by default to avoid loops, improve traffic time, and so on.

The parameters for Route are as follows:

-add Adds a route to a table. Use p to make the route persistent for subsequent sessions.

-Delete Deletes a route from the table.

-Print Prints a route.

-change Modifies an existing route.

-destination Specifies the host address.

-gateway Specifies the address of gateway for Route.

IF interface Specifies the interface for the routing table to modify.

-mask Netmask Uses the subnet mask specified by Netmask. If mask is not used, it defaults to 255.255.255.255.

-METRIC MeTRic Specifies the metric, or cost, for the route using the value Metric.

-f Clears the routing table of all gateway entries.

-p Used with -add to create a persistent route.

Nslookup

Nslookup is used to query DNS. You can think of Nslookup as a simple diagnostic client for DNS servers. It can operate in two modes: interactive and noninteractive. Use noninteractive mode to look up a single piece of data. To look up more than one piece of data, use interactive mode. To stop interactive mode at any time, press Ctrl+B. To exit from the command, type exit. If Nslookup is used without any parameters, it uses the default DNS name server for lookup.

The parameters for Nslookup are as follows:

-ComputerToFind Looks up information for the specified ComputerToFind. By default, it uses the current default DNS name server.

-Server Specifies the server as the DNS name server.

-SubCommand Specifies one or more Nslookup subcommands as a command-line option. Type a question mark (?) to display a list of subcommands available.

System Startup and Recovery

The System Startup and Recovery utility stores system startup, system failure, and debugging information. It also controls the behavior (what to do) when a system failure occurs.

To open System Startup and Recovery, right-click My Computer, select Properties, select the Advanced tab, and then click Settings under Startup and Recovery to display a property page similar to the one shown in Figure 34.15.

Figure 34.15. The Startup and Recovery page.

The Default Operating System field contains information that is displayed at startup. This information is typically the name of the operating system such as Microsoft Windows Server 2003 Enterprise server. You can edit this information by clicking the Edit button or by editing the boot.ini file. If the machine is dual-booted, there will be an entry for each operating system. The Time to Display List of Operating Systems option specifies the time the system takes to display the name of the operating system at startup. The default time is 30 seconds. This can be increased or reduced to a different time.

You can set the action to be taken when system failure occurs in the System Failure section. There are three options. The first option is Write an Event to the System Log. This action is not available on Windows Server 2003 because this action occurs by default every time a stop error occurs. The second option, Send an Administrative Alert, sends an alert. The last option, Automatically Restart, automatically reboots the system in the event of a system failure.

The Write Debugging Information section tells the system where to write debugging information when a system failure occurs. The options available include where the debugging information can be written to Small memory dump (64KB), Kernel memory dump, Complete memory dump, or (none). The Write Debugging Information To option requires a paging file on the boot volume, which should be the size of the physical RAM plus 1MB. Thus, a system with 512MB of RAM will create a paging file 513MB in size.

Memory resources can be saved if the Write Debugging Information To option is set to (none) and the Send an Administrative Alert option is unchecked. The memory that would be saved depends on the server; the drivers that enable these features require about 60 to 70KB.

Memory-Related Debugging

Many troubleshooting scenarios revolve around memory-related issues, such as an errant application or process consuming too much memory. The Windows Server 2003 Resource Kit provides many useful utilities that can assist in the troubleshooting process. However, there are two that are specifically designed for memory:

• Memory Monitor (memmonitor.exe) This command-line tool monitors a process' memory and can debug the memory in use after a specific threshold has been reached.

• Resource Leak Triage Tool (memtriage.exe) If a process takes up memory and never releases the memory back to the system, a memory leak occurs. Use this tool to monitor, log, and analyze memory usage and more easily determine whether a process is causing a memory leak.

The Software Error-Reporting Mechanism

Software errors can be reported in Windows Server 2003. The error-reporting mechanism makes this happen. The errors reported in the error-reporting mechanism can be sent to Microsoft to help improve its future products.

You can open this mechanism by right-clicking My Computer, selecting Properties, selecting the Advanced tab, and clicking the Error Reporting button to display a screen similar to the one in Figure 34.16. You can disable software error reporting by selecting the Disable Error Reporting radio button.

Figure 34.16. Error Reporting screen.

The other option is to allow software error reporting. You enable it by selecting Enable Error Reporting. Options are available to report all or one of the following: Windows Operating System, Unplanned Machine Shutdowns, Programs (you can select programs you want by clicking the Choose Programs button), and Force Queue Mode for Program Errors.

Dr. Watson for Windows

Dr. Watson for Windows is a program debugger. The Microsoft technical support team can use the information obtained and logged by Dr. Watson for troubleshooting purposes. A text file is generated whenever an error occurs. A crash dump file can also be generated when an error occurs.

Dr. Watson starts automatically when a program error occurs. However, you can also start it from a command prompt by typing drwtsn32. After Dr. Watson is started, a screen similar to the one in Figure 34.17 is shown.

Figure 34.17. Dr. Watson for Windows screen.

The log file generated by Dr. Watson can be viewed in a text editor. This file contains information such as process ID of the application, date and time of occurrence, error that occurred, program that caused the error, function name, task identifier, and so on.