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How to Use Portqry to Troubleshoot Active Directory Connectivity Issues

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This article was previously published under Q310456
SUMMARY
Portqry is a command-line utility that you can use to help troubleshoot TCP/IP connectivity issues, which you can run on Windows 2000 and Windows XP. The utility reports the port status of target Transition Control Protocol (TCP) and User Datagram Protocol (UDP) ports on a remote computer.

You can also use Portqry in the following ways:
  • To troubleshoot Active Directory issues in which you have to verify basic TCP/IP connectivity, which can be especially useful in environments with firewalls.
  • To verify connectivity to TCP/IP ports that are used by Active Directory for Lightweight Directory Access Protocol (LDAP), remote procedure call (RPC), and Domain Name Service (DNS).


Note Version 2 of Portqry.exe is now available. The Microsoft Download Center link at the end of this article has been updated to reflect the new version. Version 1.0 of Portqry.exe has been removed from the Microsoft Download Center.
MORE INFORMATION
Portqry reports the status of a port in one of three ways:
  • Listening: A process is listening on the target port on the target system. Portqry received a response from the port.
  • Not Listening: No process is listening on the target port on the target system. Portqry received an Internet Control Message Protocol (ICMP)"Destination Unreachable - Port Unreachable" message back from the target UDP port. Or, if the target port is a TCP port, Portqry received a TCP acknowledgement packet with the Reset flag set.
  • Filtered: The target port on the target system is being filtered. Portqry did not receive a response from the target port. A process may or may not be listening on the port. By default, TCP ports are queried three times and UDP ports are queried once before reporting the target port is filtered.
With Portqry, you can also query an LDAP service. It knows how to send an LDAP query (by using UDP and TCP) and interpret an LDAP server's response to the query. The response from the LDAP server is parsed, formatted and returned to the user.

Example

When you run the following command:
portqry -n myserver -p udp -e 389
Portqry automatically resolves UDP port 389 using the %SystemRoot%\System32\Drivers\...\Services file that every Windows 2000 and Windows XP system has by default. If it resolves the port to the LDAP service, it sends an unformatted user datagram to UDP port 389 on the target system. Portqry will not receive a response from the port as the LDAP service only responds to a properly formatted LDAP query. Portqry will report that the port is listening or filtered. Portqry will then send a properly formatted LDAP query to UDP port 389. If it receives a response to the query, it returns the entire response to the user and report that the port is listening. If portqry does not receive a response to the query, it reports that the port is filtered.

Sample Output

C:\>portqry -n mydc.reskit.com -e 389 -p udp  Querying target system called:  mydc.reskit.com  Attempting to resolve name to IP address...  Name resolved to 169.254.0.14  UDP port 389 (unknown service): LISTENING or FILTERED  Sending LDAP query to UDP port 389...  LDAP query response:  currentdate: 10/11/2001 23:10:21 (unadjusted GMT) subschemaSubentry: CN=Aggregate,CN=Schema,CN=Configuration,DC=reskit,DC=com dsServiceName: CN=NTDS  Settings,CN=mydc,CN=Servers,CN=eu,CN=Sites,CN=Configuration,DC=reskit,DC=com namingContexts: DC=reskit,DC=com defaultNamingContext: DC=reskit,DC=com schemaNamingContext: CN=Schema,CN=Configuration,DC=reskit,DC=com configurationNamingContext: CN=Configuration,DC=reskit,DC=com rootDomainNamingContext: DC=reskit,DC=com supportedControl: 1.2.840.113556.1.4.319 supportedLDAPVersion: 3 supportedLDAPPolicies: MaxPoolThreads highestCommittedUSN: 815431405 supportedSASLMechanisms: GSSAPI dnsHostName: MYDC.reskit.com ldapServiceName: reskit.com:mydc$@RESKIT.COM serverName:  CN=MYDC,CN=Servers,CN=EU,CN=Sites,CN=Configuration,DC=reskit,DC=com supportedCapabilities: 1.2.840.113556.1.4.800 isSynchronized: TRUE isGlobalCatalogReady: TRUE  ======== End of LDAP query response ======== UDP port 389 is LISTENING 					
In this sample, port 389 is listening and from the output it can be determined which LDAP service is listening on the port and some details about its configuration. This information may also be useful in troubleshooting various problems.

Portqry knows how to send a query to the RPC end point mapper (using UDP and TCP) and interpret the response. This query will dump all of the end points currently registered with the RPC end point mapper. The response from the end point mapper is parsed, formatted and returned to the user.

Example

When you run the following command:
portqry -n mydc.reskit.com -p udp -e 135

Sample Output

Querying target system called:  mydc.reskit.com  Attempting to resolve name to IP address...  Name resolved to 169.254.0.18  UDP port 135 (epmap service): LISTENING or FILTERED Querying Endpoint Mapper Database... Server's response:  UUID: ecec0d70-a603-11d0-96b1-00a0c91ece30 NTDS Backup Interfacencacn_np:\\\\MYDC[\\PIPE\\lsass]  UUID: 16e0cf3a-a604-11d0-96b1-00a0c91ece30 NTDS Restore Interfacencacn_np:\\\\MYDC[\\PIPE\\lsass]  UUID: e3514235-4b06-11d1-ab04-00c04fc2dcd2 MS NT Directory DRS Interfacencacn_ip_tcp:169.254.0.18[1027]  UUID: f5cc59b4-4264-101a-8c59-08002b2f8426 NtFrs Servicencacn_ip_tcp:169.254.0.18[1130]  UUID: d049b186-814f-11d1-9a3c-00c04fc9b232 NtFrs APIncacn_ip_tcp:169.254.0.18[1130]  UUID: d049b186-814f-11d1-9a3c-00c04fc9b232 NtFrs APIncacn_np:\\\\MYDC[\\pipe\\00000580.000]  Total endpoints found: 6  ==== End of RPC Endpoint Mapper query response ====  UDP port 135 is LISTENING					
In this example, port 135 is listening and from the output it can be determined which services or applications have been registered with the target server's RPC end point mapper database. The output includes each application's Universally Unique Identifier (UUID), annotated name (if one exists), the protocol the application uses, the network address that the application is bound to, and the application's end point (port number, named pipe, and so forth, in square brackets). This information may also be useful in troubleshooting various problems.

Portqry can send a properly formatted DNS query (using UDP or TCP). The utility will send a DNS query for "portqry.microsoft.com." Portqry then waits for a response from the target DNS server. Whether the DNS response to the query is negative or positive is irrelevant since any response indicates that the port is listening.

Portqry.exe is available for download from the Microsoft Download Center. To download Portqry.exe, visit the following Microsoft Web site:Important The PortQueryUI tool provides a graphical user interface is available for download. PortQueryUI has several features that can make using PortQry easier. To obtain the PortQueryUI tool, visit the following Microsoft Web site:
port scanner probe telnet ldap smtp pop3 imap ftp dns netbios rpc test connectivity state ad
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Article ID: 310456 - Last Review: 02/21/2007 22:12:36 - Revision: 4.3

  • Microsoft Windows 2000 Server
  • Microsoft Windows 2000 Advanced Server
  • Microsoft Windows 2000 Professional Edition
  • Microsoft Windows XP Professional
  • kbenv kberrmsg kbhowto kbnetwork KB310456
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