NSLookup IP Address dialog help
Use the NSLookup IP Address dialog to issue a z/OS Communications
Server NSLOOKUP command to query name servers so that you can locate
information about network nodes, examine the contents of a name-server
database, or establish the accessibility of name servers.
The NSLookup IP Address dialog has two areas: a command
input area where you specify the characteristics of the command
you want to issue and the command output area
where the results of the command are displayed.
The only required field is the Domain Name or
Address field and it is prefilled with the IP address from the
row or bar-graph bar from which you issued the take action
command.
The remaining fields in this dialog box are prefilled with the
default values when the dialog is initialized. You can change the
value of any modifiable field prior to invoking the command. Field-level
validation is performed prior to command execution. You are prompted
by the dialog to correct invalid data.
Complete explanations of the fields in this dialog are found in
the IBM z/OS Communications Server: IP System Administrator's Commands book for your level of z/OS. Brief
explanations of these fields follow.
- Domain Name or Address: Specifies the destination
domain, defined as a domain name or IP address. The command queries
the name server for information about the current query type for the
Domain Name (the default query type is A for address query). If the
domain name starts with an underscore (_), you must prefix the domain
name with the escape character (\). The format of the Address reverses
the components of a typical IP address and generates a pointer type
(PTR) query to the name server for the in-addr.arpa domain
mapping of the address to a domain name.
- Server Name or Address: Specifies the destination
domain name server (DNS), defined as a server name or IP address.
The Server Name directs the default name server to map server_name
to an IP address and then use the name server at that IP address.
The Address specifies the IP address of the name server to be queried
other than the default name server. A query for the address in the in-addr.arpa domain is initially made to the default
name server to map the IP address to a domain name for the server.
- Query Type: Specifies the type of information
returned by queries. The default value for Query Type is A (a
host address). Valid values for Query Type are as follows:
- A
- A host address (the default).
- HINFO
- The processor type and operating system of the host system.
- MX
- The mail exchanger for the domain, specified in the Domain Name
or Address field.
- NS
- The authoritative name server for the domain, specified in the
Domain Name or Address field.
- PTR
- A pointer to another part of the domain name space.
- SOA
- Identifies the start of a zone of authority.
- SRV
- Information about well-known network services.
- Class: Sets the class of information returned
by queries. The default value for Class is IN (Internet).
Valid values for Class are as follows:
- IN
- Internet (the default)
- ANY
- Any
- CHAOS
- CHAOSnet, a LAN protocol developed by Massachusetts Institute
of Technology (MIT). Zone data for CHAOSnet can be specified with
the CHAOS class.
- HESIOD
- An information service from MIT's Project Athena used to
share information about various systems databases, such as users,
groups, or printers.
- Port: Specifies the port number to use when
contacting the name server. The Domain Name System is a well-known
service and has been allocated port 53. The NSLOOKUP command uses
port 53 by default, but the port option enables
you to specify another port to access. The range for valid values
is from 1 to 65535.
- Retry: Specifies the number of times a request
is resent. When a request is sent and the timeout period expires for
a response, the request is resent until the value specified has been
exceeded. The value specified determines the number of attempts made
to contact the name server. The range for valid values is from 1 to
2147483647. The default value is 1.
Setting
a Retry limit to 0 disables the NSLOOKUP command from contacting the
name server. The result is an error message no response from server.
The retry algorithm for the NSLOOKUP command uses both the Retry value
and the Timeout period. Each time a request is resent, the Timeout
period for the request is twice the Timeout period used for the last
attempt.
- Timeout: Specifies the number of seconds
to wait before timing out of a request. The range for valid values
is from 1 to 2147483647. The default value for the Timeout interval
is 30 seconds.
- All: Enables you to print the current values
of the internal state variables. This option does not alter the internal
state of the NSLOOKUP command.
- Brackets: Causes output to display with
brackets. The default is nobrackets.
- Defname: Directs the NSLOOKUP command to
append the default domain name to an unqualified domain name in a
query. The default is nodefname.
- Recurse: Directs the NSLOOKUP command to
request a recursive query when querying a name server. The default
is recurse.
- VC: Specifies to use a virtual circuit (TCP
connection) to transport queries to the name server or datagrams (UDP).
The default is retrieved from the TCPIP.DATA data set. The default
is novc.
- Debug: Specifies one of the three options
below, as specified by selecting the corresponding radio button. The
default is nodebug.
- db2
- Directs the NSLOOKUP command to enable extra debugging mode.
Using d2 also enables debug mode. The default
is nod2.
Note:
To obtain all alias
names for a host when using reverse query, you must set the d2 option.
- debug
- Directs the NSLOOKUP command to print debugging information
for each query and its corresponding response.
- nodebug
- Directs the NSLOOKUP command to not print debugging information
for each query and its corresponding response. This option also disables d2.
When you have completed the fields in the NSLookup IP Address dialog,
click OK to issue the specified NSLOOKUP command.
Click Cancel to close the NSLookup IP Address
dialog. Click Help to invoke the online help.