NSLOOKUP options

The configuration options of NSLOOKUP determine the operation and results of your name server queries. These options can be specified in command-mode queries, interactive-mode queries, or in the user_id.NSLOOKUP.ENV data set. When you include NSLOOKUP options with the initial NSLOOKUP command the (-) operand must immediately precede the option. If you specify NSLOOKUP options while in interactive mode, the SET subcommand must precede the option. Specifying NSLOOKUP options in the user_id.NSLOOKUP.ENV data set is optional. Use the SET subcommand before the option if you want to reset the option value. The (-) operand is not valid preceding options in the user_id.NSLOOKUP.ENV data set.

For example, to specify a name server (NS) type record lookup for the domain name fourex.oz in command mode you enter:

nslookup -querytype=ns fourex.oz

To submit the same request using interactive mode enter the following sequence:

nslookup
set querytype=ns
fourex.oz

To make querytype of NS a default option for your NSLOOKUP commands, place one of the following statements in the user_id.NSLOOKUP.ENV data set:

set querytype=ns
querytype=ns

The optional data set user_id.NSLOOKUP.ENV. contains only NSLOOKUP options and defines the NSLOOKUP defaults. If the user_id.NSLOOKUP.ENV data set exists, the NSLOOKUP options are read from the data set and executed before any queries are made. You must enter each option on a separate line. Blank lines are ignored.

The following example shows the contents of the user_id.NSLOOKUP.ENV data set:

set domain=powers.oz
querytype=HINFO
set norecurse
vc

Option

all

Enables you to print the current values of the internal state variables. This option does not alter the internal state of NSLOOKUP.

class=class

Sets the class of information returned by queries. The class must be identified by its mnemonic. The minimum abbreviation for this option is cl.

d2

Directs NSLOOKUP to enable extra debugging mode. Using d2 also enables debug mode.

Note: To obtain all alias names for a host when using reverse query, you must set the d2 option.

nod2

Directs NSLOOKUP to disable extra debugging mode. The default is nod2.

debug

Directs NSLOOKUP to print debugging information for each query and its corresponding response. The minimum abbreviation is deb and nodeb.

nodebug

Directs NSLOOKUP to not print debugging information for each query and its corresponding response. This option also disables d2. The minimum abbreviation is nodeb. This is the default.

defname

Directs NSLOOKUP to append the default domain name to an unqualified domain name in a query. This value is the default. If the search list is also enabled, then the domain names specified in the search list will also be appended until a query is resolved or until no more domain names are left in the search list.

The default domain name is initially obtained from the TCPIP.DATA data set, but can be changed using the domain=name option. The minimum abbreviation for this option is def.

nodefname

Directs NSLOOKUP to not append the default domain name to an unqualified domain name in a query.

If you specify this option, the domain name specified in the query is passed to the server without modification. The search list will not be used, even if it is enabled. The minimum abbreviation for this option is nodef.

domain=name

Sets the default domain name to name. Initially, the default domain name is obtained from the TCPIP.DATA data set. The validity of name is not verified. This option also updates the search list. The search list contains the domain specified and the parents of the default domain if it has at least two components in its name. For example, if the default domain is wurrup.forex.oz, the search list contains wurrup.forex.oz and forex.oz. Use the SET srchlist command to specify a different search list. The minimum abbreviation for this option is do.

ignoretc

Directs NSLOOKUP on the handling of truncated responses. The name server indicates, in the response header, that the complete query response did not fit into a single UDP packet and has been truncated.

Specifying ignoretc directs NSLOOKUP to ignore the truncation condition when it is set in the response by the name server.

NSLOOKUP does not handle responses greater than 512 characters in length. Responses greater than 512 characters are truncated and the internal truncation flag is set. This condition is revealed only when the debug option is enabled. The minimum abbreviation for this option is ig.

noignorectc

Directs NSLOOKUP to automatically retry the query using a TCP connection when a response is sent with the truncation indicator set. This is the default. The minimum abbreviation for this option is noig.

port=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. NSLOOKUP uses port 53 by default, but the port option enables you to specify another port to access. The minimum abbreviation for this option is po.

querytype=type

Specifies the type of information returned by queries. The initial query type is A (address information). See the z/OS Communications Server: IP Configuration Reference for detailed information about available query types.

NSLOOKUP cannot generate queries about type NULL. However, it can accept responses containing resource records of type NULL. In this case, NSLOOKUP displays the number of bytes returned in the NULL record. Global queries that return all resource records for a specific domain name are specified by the wildcard value ANY. The minimum abbreviation for this option is q.

The type=type option is accepted by NSLOOKUP as a synonym for the querytype=type option.

recurse

Directs NSLOOKUP to request a recursive query when querying a name server. The minimum abbreviation for this option is rec. This is the default.

norecurse

Specifies that a recursive query is not returned. The minimum abbreviation for this option is norec.

retry=limit

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 in limit has been exceeded. The value specified in limit determines the number of attempts made to contact the name server. The default value for limit is retrieved from the TCPIP.DATA data set.

Setting limit to 0 disables NSLOOKUP from contacting the name server. The result is an error message no response from server.

The retry algorithm for NSLOOKUP uses both the limit value and the timeout period. The minimum abbreviation for this option is ret.

root=name

Specifies the name of a root server. The root server is ns.nic.ddn.mil by default.

search

Directs NSLOOKUP to enable the use of a search list. The minimum abbreviation for this option is sea.

nosearch

Directs NSLOOKUP to disable the use of a search list. The minimum abbreviation for this option is nosea.

srchlist=[domain⁄domain⁄...]

Specifies one or up to three domain names to be appended to non-fully-qualified domain names when attempting to resolve the host name. Each domain name specified is tried in turn until a match is found or no domain names are left to try.

This option also directs the default domain to be set to the first domain name specified in the search list. The minimum abbreviation for this option is srchl.

timeout=interval

Specifies the number of seconds to wait before timing out of a request. The default for interval is retrieved from the TCPIP.DATA data set. The minimum abbreviation for this option is t.

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.

novc

Specifies to not use a virtual circuit to transport queries to the name server or datagrams. This option is the default.