This material contains examples of NSLOOKUP command-mode queries, and interactive-mode queries using the various options available for NSLOOKUP commands.
In Figure 1, the router
wurrup has two IP addresses and there are two name servers, wurrup
being the primary name server. This network is described by a single
zone in the domain naming hierarchy stored in the name servers.
Figure 1. Hierarchical naming tree—A
TCP⁄IP network
The following examples show how to use NSLOOKUP to extract information from a name server. The queries are executed from the z/OS® host uluru on the network described in Figure 1.
The following examples are command-mode queries.
- To make a simple address query:
User: nslookup toolah.fourex.oz wurrup.fourex.oz System: Server: wurrup Address: 101.3.104.12 Name: toolah.fourex.oz Address: 101.3.100.2 - To specify a name server (NS) type record lookup:
User: nslookup -querytype=ns fourex.oz System: Server: canetoad Address: 101.3.104.40 fourex.oz nameserver = wurrup.fourex.oz fourex.oz nameserver = canetoad.fourex.oz wurrup.fourex.oz internet address = 101.3.100.12 wurrup.fourex.oz internet address = 101.3.104.12 canetoad.fourex.oz internet address = 101.3.104.40 - To specify a different default domain name to be appended to an
unqualified domain name given as input:
User: nslookup -do=fourex.oz uluru System: Server: canetoad.fourex.oz Address: 101.3.104.40 Name: uluru.fourex.oz Address: 101.3.104.38 - To specify a list of domain names to be appended in turn to the
unqualified host name when attempting to resolve it:
User: nslookup -srchlist=nowhere.oz/fourex.oz uluru System: Server: canetoad.fourex.oz Address: 101.3.104.40 Name: uluru.fourex.oz Address: 101.3.104.38
User:
nslookup - wurrup
System: Default Server: wurrup
Address: 101.3.104.12- Show the default flag settings:
User: set all Default Server: wurrup.fourex.oz Address: 101.3.104.12 Set options: nodebug defname nosearch recurse nod2 novc noignoretc port=53 querytype=A class=IN timeout=60 retry=1 root=ns.nic.ddn.mil. domain=FOUREX.OZ srchlist=FOUREX.OZ - Perform a simple address query:
User: toolah System: Server: wurrup Address: 101.3.104.12 Name: toolah.FOUREX.OZ Address: 101.3.100.2 - Set the query record type to HINFO, and perform another query:
User: set q=HINFO toolah System: Server: wurrup Address: 101.3.104.12 toolah.FOUREX.OZ CPU = RS6000 OS = AIX3.1 - Find out the name servers available for a domain:
User: set q=NS fourex.oz System: Server: wurrup Address: 101.3.104.12 fourex.oz nameserver = wurrup.fourex.oz fourex.oz nameserver = canetoad.fourex.oz wurrup.fourex.oz internet address = 101.3.100.12 wurrup.fourex.oz internet address = 101.3.104.12 canetoad.fourex.oz internet address = 101.3.104.40 - Change the current server from wurrup to canetoad and make more
queries:
User: server canetoad System: Default Server: canetoad.FOUREX.OZ Address: 101.3.104.40 User: set q=A gecko System: Server: canetoad.FOUREX.OZ Address: 101.3.104.40 Name: gecko.FOUREX.OZ Address: 101.3.100.90 - Enable debugging and execute a simple query to see the result,
and then disable debugging:
User: set deb wurrup System: Server: canetoad.FOUREX.OZ Address: 101.3.104.40 res_mkquery(0, wurrup.FOUREX.OZ, 1, 1) ------------ Got answer: HEADER: opcode = QUERY, id = 7, rcode = NOERROR header flags: response, auth. answer, want recursion, recursion avail questions = 1, answers = 2, authority records = 0, additional = 0 QUESTIONS: wurrup.FOUREX.OZ, type = A, class = IN ANSWERS: -> wurrup.FOUREX.OZ internet address = 101.3.104.12 ttl = 9999999 (115 days 17 hours 46 mins 39 secs) -> wurrup.FOUREX.OZ internet address = 101.3.100.12 ttl = 9999999 (115 days 17 hours 46 mins 39 secs) ------------ Name: wurrup.FOUREX.OZ Addresses: 101.3.104.12, 101.3.100.12 User: set nodeb - Find all addresses in the fourex.oz domain using
the ls option:
User: ls fourex.oz System: [canetoad.FOUREX.OZ] fourex.oz server = wurrup.fourex.oz wurrup 101.3.100.12 wurrup 101.3.104.12 fourex.oz server = canetoad.fourex.oz canetoad 101.3.104.40 gecko 101.3.100.90 wurrup 101.3.100.12 wurrup 101.3.104.12 galah 101.3.100.20 bandicoot 101.3.104.52 toolah 101.3.100.2 canetoad 101.3.104.40 loopback 127.0.0.1 uluru 101.3.104.38 - Find all aliases in the fourex.oz domain, then
exit from NSLOOKUP interactive mode:
User: ls -a fourex.oz System: [canetoad.FOUREX.OZ] localhost loopback.fourex.oz infoserver wurrup.fourex.oz pabxserver wurrup.fourex.oz User: exit - To display a summary of available commands:
User: help System: Commands: (identifiers are shown in uppercase, <> means optional) NAME - print info about the host/domain NAME using default server NAME1 NAME2 - as above, but use NAME2 as server help or ? - print info on common commands; see nslookup man for details set OPTION - set an option all - print options, current server and host <no>debug - print debugging information <no>d2 - print exhaustive debugging information <no>defname - append domain name to each query <no>recurse - ask for recursive answer to query <no>vc - always use a virtual circuit domain=NAME - set default domain name to NAME srchlist=N1</N2/.../N6> - set domain to N1 and search list to N1,N2, etc. root=NAME - set root server to NAME retry=X - set number of retries to X timeout=X - set initial time-out interval to X seconds querytype=X - set query type, e.g., A,ANY,CNAME,HINFO,MX,NS,PTR,SOA,WKS type=X - synonym for querytype class=X - set query class to one of IN (Internet), CHAOS, HESIOD or ANY server NAME - set default server to NAME, using current default server lserver NAME - set default server to NAME, using initial server finger <USER> - finger the optional NAME at the current default host root - set current default server to the root ls <opt> DOMAIN ^> DATASET| - list addresses in DOMAIN (optional: output to DATASET) -a - list canonical names and aliases -h - list HINFO (CPU type and operating system) -s - list well-known services -d - list all records -t TYPE - list records of the given type (e.g., A,CNAME,MX, etc.) view DATASET - sort an 'ls' output file and view it with more exit - exit the program - To find information for all the users currently logged in on the
node specified in the last address query:
User: finger System: [canetoad.FOUREX.OZ] Further output to be generated .... - To set the default domain name to fourex.oz,
use the command
set domain=fourex.ozThis command overrides the DOMAINORIGIN statement in the tcpip.TCPIP.DATA data set.
- To specify that the default domain name is to be appended to an unqualified domain name given in a query, use the SET defname command.
- To request that the query be resent three times if the timeout period expires for a response, use the SET retry=3 command. A value of 3 is the maximum valid value.