Interactive mode enables you to query one or more name servers repeatedly for information about various hosts and domains, to display that information on your console, and, in some cases, to write response data to a file. nslookup is a synonym for the onslookup command in the z/OS UNIX shell. nslookup command syntax is the same as that for the onslookup command.
You
can enter the interactive mode under the following conditions only:
- No arguments are supplied on command invocation. The default name server is used.
- The first argument is a hyphen (-), and the second argument is the host name or IP address of a name server.
In interactive mode:
- An initial query is made to the selected name server to verify that the server is accessible.
- All subsequent interactive queries are sent to that server unless you specify another server using the server or lserver subcommands.
- The command line length must be less than 256 characters.
- To treat a built-in command as a host name, precede it with an escape character (\). An unrecognized command is interpreted as a host name.
For a complete list and description of onslookup options, see onslookup options. See nslookup versions for listing of valid commands and start options.
Format
- Interactive mode
>>-onslookup--+-----------------+--+------------------+--------->
| .-------------. | +- -server_name----+
| V | | '- -server_address-'
'---| -Option |-+-'
>--Enter-------------------------------------------------------><
- Interactive commands, subsequent queries
>>-+----------------------+--Enter-----------------------------><
+-exit-----------------+
+-host--+--------+-----+
| '-server-' |
+-lserver--+-name----+-+
| '-address-' |
+-server--+-name----+--+
| '-address-' |
'-set--| option |------'
Parameters
- -Option
- For a description of the onslookup options, see onslookup options.
- -server_name
- Directs the default name server to map -server_name to an IP address and then uses the name server at that address. This argument is optional. The default is the default name server found by the search order described in onslookup configuration. This name can be a name that resolves to an IPv4 or an IPv6 address.
- -server_address
- Specifies the IP address of the name server to be queried other than the default name server. A query for the address is initially made to the default name server to map the IP address to a domain name for the server. This argument is optional. The default is the default name server found by the search order described in onslookup configuration. This can be an IPv4 or an IPv6 address.
- exit
- Exits from onslookup interactive mode.
- host
- host is the host name or IP address you want the name server to resolve. Use this format to look up information for a host using the current default server or using server if specified. If host is an IP address and the query type is A or PTR, the name of the host is returned. If host is a name and does not have a trailing period, the default domain name is appended to the name. (This behavior depends on the state of the set options -domain, -srchlist, -defname, and -search.) To look up a host not in the current domain, append a period to the name.
- lserver
- Change the default server to one determined by name or address.
This command uses the initial server to look up information about
the new server. This can be a name that resolves to an IPv4 or an
IPv6 address, or an actual IPv4 or IPv6 address.
If an authoritative answer cannot be found, the names of servers that might have the answer are returned.
- server
- Change the default server to one determined by name or address.
This command uses the current default server to look up information
about the new server. This can be a name that resolves to an IPv4
or IPv6 address, or an actual IPv4 or IPv6 address.
If an authoritative answer cannot be found, the names of servers that might have the answer are returned.
- set keyword
- Allows changes to query environment. The following describes the keyword and
values that can be used.
- all
- Prints the current values of the frequently used options to set. Information about the current default server and host is also printed.
- class=query_class
- The class specifies the protocol group of the information. The class changes the query class. See the z/OS Communications Server: IP Configuration Reference for detailed information about valid query types. The default class is IN. The keyword class can be abbreviated as cl.
- [no]d2
- Turn exhaustive debugging mode on (d2) or off (nod2). You will not see any difference between debug, d2 and trace resolver. This turns on nslookup internal trace. The default is nod2.
- [no]debug
- Turn basic debugging mode on (debug) or off (nodebug). Information is printed about the packet sent to the server and the resulting answer. The default is nodebug. The keyword debug can be abbreviated as deb.
- [no]defname
- If set, append the default domain name to a single-component lookup request (one that does not contain a period). The default is defname. The keyword defname can be abbreviated as def. This is equivalent to the [no]search option. Specifying the '-domain=' option also causes the default domain name to be appended to the name being queried.
- domain=name
- Change the default domain name to name. The default domain name is appended to a lookup request depending on the state of the defname and search options. The keyword domain can be abbreviated as do. This also causes the -search option to be turned on. Also, this becomes the default search list and overrides the default domain specified in the resolver configuration file.
- port=value
- Change the default TCP/UDP name server port to value. The default port number is 53. The keyword port can be abbreviated as po.
- querytype=type
-
- The keyword querytype can be abbreviated as type.
- The keyword querytype can also be abbreviated as qu.
Change the type of information query type. See the z/OS Communications Server: IP Configuration Reference for detailed information about valid query types. The default value is A.
- [no]recurse
- Tell the name server to query other servers if it does not have the information. The default is recurse. The keyword recurse can be abbreviated as rec.
- retry=number
- Set the number of retries to number. When a reply to a request is not received within a certain amount of time (changed with set timeout), the timeout period is doubled and the request is resent. The retry value controls how many times a request is sent before giving up. The default is 4. The keyword retry can be abbreviated as ret.
- [no]search
- If the lookup request contains at least one period but does not end with a trailing period, append the domain names in the domain search list to the request until an answer is received. The default is search. The keyword search can be abbreviated as sea. This is equivalent to the [no]defname option.
- timeout=number
- Change the initial timeout interval for waiting for a reply to number seconds. Each retry doubles the timeout period. The default is 5 seconds. The kewyord timeout can be abbreviated as t.
- [no]vc
- Always use a virtual circuit (TCP) when sending requests to the server. The default is novc. The keyword vc can be abbreviated as v.