
NSLOOKUP(8)             FreeBSD System Manager's Manual            NSLOOKUP(8)

NNAAMMEE
     nnssllooookkuupp - query Internet name servers interactively

SSYYNNOOPPSSIISS
     nnssllooookkuupp [--ooppttiioonn _._._.] [_h_o_s_t_-_t_o_-_f_i_n_d | --[_s_e_r_v_e_r]]

DDEESSCCRRIIPPTTIIOONN
     NNssllooookkuupp is a program to query Internet domain name servers.  NNssllooookkuupp
     has two modes: interactive and non-interactive.  Interactive mode allows
     the user to query name servers for information about various hosts and
     domains or to print a list of hosts in a domain.  Non-interactive mode is
     used to print just the name and requested information for a host or do-
     main.

AARRGGUUMMEENNTTSS
     Interactive mode is entered in the following cases:

     a)    when no arguments are given (the default name server will be used),

     b)    when the first argument is a hyphen (-) and the second argument is
           the host name or Internet address of a name server.

     Non-interactive mode is used when the name or Internet address of the
     host to be looked up is given as the first argument. The optional second
     argument specifies the host name or address of a name server.

     The options listed under the ``set'' command below can be specified in
     the _._n_s_l_o_o_k_u_p_r_c file in the user's home directory if they are listed one
     per line.  Options can also be specified on the command line if they pre-
     cede the arguments and are prefixed with a hyphen.  For example, to
     change the default query type to host information, and the initial time-
     out to 10 seconds, type:

                   nslookup -query=hinfo  -timeout=10

IINNTTEERRAACCTTIIVVEE CCOOMMMMAANNDDSS
     Commands may be interrupted at any time by typing a control-C.  To exit,
     type a control-D (EOF) or type exit. 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 (.& .) NN..BB..:: unrecognized command will be
     interpreted as a N.B.:0 0N.B.:1

     _h_o_s_t [_s_e_r_v_e_r]
              Look up information for _h_o_s_t using the current default server or
              using _s_e_r_v_e_r, if specified.  If _h_o_s_t is an Internet address and
              the query type is A or PTR, the name of the host is returned.
              If _h_o_s_t is a name and does not have a trailing period, the de-
              fault domain name is appended to the name.  (This behavior de-
              pends on the state of the sseett options ddoommaaiinn, ssrrcchhlliisstt, ddeeffnnaammee,
              and sseeaarrcchh.)

              To look up a host not in the current domain, append a period to
              the name.

     sseerrvveerr _d_o_m_a_i_n

     llsseerrvveerr _d_o_m_a_i_n
              Change the default server to _d_o_m_a_i_n; llsseerrvveerr uses the initial
              server to look up information about _d_o_m_a_i_n, while sseerrvveerr uses
              the current default server.  If an authoritative answer can't be
              found, the names of servers that might have the answer are re-

              turned.

     rroooott     Changes the default server to the server for the root of the do-
              main name space.  Currently, the host ns.internic.net is used.
              (This command is a synonym for ``llsseerrvveerr nnss..iinntteerrnniicc..nneett''.) The
              name of the root server can be changed with the ``sseett rroooott''
              command.

     ffiinnggeerr [_n_a_m_e] [>> _f_i_l_e_n_a_m_e]

     ffiinnggeerr [_n_a_m_e] [>>>> _f_i_l_e_n_a_m_e]
              Connects with the finger server on the current host.  The cur-
              rent host is defined when a previous lookup for a host was suc-
              cessful and returned address information (see the ``sseett
              qquueerryyttyyppee==AA'' command).  The _n_a_m_e is optional.  >> and >>>> can be
              used to redirect output in the usual manner.

     llss [_o_p_t_i_o_n] _d_o_m_a_i_n [>> _f_i_l_e_n_a_m_e]

     llss [_o_p_t_i_o_n] _d_o_m_a_i_n [>>>> _f_i_l_e_n_a_m_e]
              List the information available for _d_o_m_a_i_n, optionally creating
              or appending to _f_i_l_e_n_a_m_e. The default output contains host names
              and their Internet addresses.  _O_p_t_i_o_n can be one of the follow-
              ing:

              --tt _q_u_e_r_y_t_y_p_e
                    lists all records of the specified type (see _q_u_e_r_y_t_y_p_e be-
                    low).

              --aa    lists aliases of hosts in the domain; synonym for ``--tt
                    CNAME''.

              --dd    lists all records for the domain; synonym for ``--tt ANY''.

              --hh    lists CPU and operating system information for the domain;
                    synonym for ``--tt HINFO''.

              --ss    lists well-known services of hosts in the domain; synonym
                    for ``--tt WKS''.

              When output is directed to a file, hash marks are printed for
              every 50 records received from the server.

     vviieeww _f_i_l_e_n_a_m_e
              Sorts and lists the output of previous llss command(s) with
              more(1).

     hheellpp

     ??        Prints a brief summary of commands.

     eexxiitt     Exits the program.

     sseett _k_e_y_w_o_r_d [=_v_a_l_u_e]
              This command is used to change state information that affects
              the lookups.  Valid keywords are:

              aallll      Prints the current values of the frequently-used op-
                       tions to sseett. Information about the  current default
                       server and host is also printed.

              ccllaassss==_v_a_l_u_e
                       Change the query class to one of:



                       IN        the Internet class

                       CHAOS     the Chaos class

                       HESIOD    the MIT Athena Hesiod class

                       ANY       wildcard (any of the above)

                       The class specifies the protocol group of the informa-
                       tion.

                       (Default = IN; abbreviation = ccll)

              [nnoo] ddeebbuugg
                       Turn debugging mode on.  A lot more information is
                       printed about the packet sent to the server and the re-
                       sulting answer.

                       (Default = nnooddeebbuugg; abbreviation = [nnoo]ddeebb)

              [nnoo] dd22  Turn exhaustive debugging mode on.  Essentially all
                       fields of every packet are printed.

                       (Default = nnoodd22)

              ddoommaaiinn==_n_a_m_e
                       Change the default domain name to _n_a_m_e. The default do-
                       main name is appended to a lookup request depending on
                       the state of the ddeeffnnaammee and sseeaarrcchh options.  The do-
                       main search list contains the parents of the default
                       domain if it has at least two components in its name.
                       For example, if the default domain is CC.Berkeley.EDU,
                       the search list is CC.Berkeley.EDU and Berkeley.EDU.
                       Use the ``sseett ssrrcchhlliisstt'' command to specify a different
                       list.  Use the ``sseett aallll'' command to display the list.

                       (Default = value from hostname(1),  _/_e_t_c_/_r_e_s_o_l_v_._c_o_n_f,
                       or LOCALDOMAIN; abbreviation = ddoo)

              ssrrcchhlliisstt==_n_a_m_e_1_/_n_a_m_e_2_/_._._.
                       Change the default domain name to _n_a_m_e_1 and the domain
                       search list to _n_a_m_e_1, _n_a_m_e_2, etc.  A maximum of 6 names
                       separated by slashes (/) can be specified.  For exam-
                       ple,

                             set srchlist=lcs.MIT.EDU/ai.MIT.EDU/MIT.EDU

                       sets the domain to lcs.MIT.EDU and the search list to
                       the three names.  This command overrides the default
                       domain name and search list of the ``sseett ddoommaaiinn'' com-
                       mand.  Use the ``sseett aallll'' command to display the list.

                       (Default = value based on hostname(1),
                       _/_e_t_c_/_r_e_s_o_l_v_._c_o_n_f, or LOCALDOMAIN; abbreviation = ssrrcchhll)

              [nnoo] ddeeffnnaammee
                       If set, append the default domain name to a single-com-
                       ponent lookup request (i.e., one that does not contain
                       a period).

                       (Default = ddeeffnnaammee; abbreviation = [nnoo]ddeeffnnaammee)

              [nnoo] sseeaarrcchh
                       If the lookup request contains at least one period but
                       _d_o_e_s_n_'_t end with a trailing period, append the domain
                       names in the domain search list to the request until an
                       answer is received.

                       (Default = sseeaarrcchh; abbreviation = [nnoo]sseeaa)

              ppoorrtt==_v_a_l_u_e
                       Change the default TCP/UDP name server port to _v_a_l_u_e.

                       (Default = 53; abbreviation = ppoo)

              qquueerryyttyyppee==_v_a_l_u_e

              ttyyppee==_v_a_l_u_e
                       Change the type of information query to one of:

                       A         the host's Internet address.

                       CNAME     the canonical name for an alias.

                       HINFO     the host CPU and operating system type.

                       MINFO     the mailbox or mail list information.

                       MX        the mail exchanger.

                       NS        the name server for the named zone.

                       PTR       the host name if the query is an Internet ad-
                                 dress; otherwise, the pointer to other infor-
                                 mation.

                       SOA       the domain's ``start-of-authority'' informa-
                                 tion.

                       TXT       the text information.

                       UINFO     the user information.

                       WKS       the supported well-known services.

                       Other types (ANY, AXFR, MB, MD, MF, NULL) are described
                       in the RFC-1035 document.

                       (Default = A; abbreviations = qq, ttyy)

              [nnoo] rreeccuurrssee
                       Tell the name server to query other servers if it does
                       not have the information.

                       (Default = rreeccuurrssee; abbreviation = [nnoo]rreecc)

              rreettrryy==_n_u_m_b_e_r
                       Set the number of retries to _n_u_m_b_e_r. When a reply to a
                       request is not received within a certain amount of time
                       (changed with ``sseett ttiimmeeoouutt''), the timeout period is
                       doubled and the request is resent.  The retry value
                       controls how many times a request is resent before giv-
                       ing up.

                       (Default = 4, abbreviation = rreett)

              rroooott==_h_o_s_t
                       Change the name of the root server to _h_o_s_t. This af-
                       fects the ``rroooott'' command.



                       (Default = nnss..iinntteerrnniicc..nneett..; abbreviation = rroo)

              ttiimmeeoouutt==_n_u_m_b_e_r
                       Change the initial timeout interval for waiting for a
                       reply to _n_u_m_b_e_r seconds. Each retry doubles the timeout
                       period.

                       (Default = 5 seconds; abbreviation = ttii)

              [nnoo] vvcc  Always use a virtual circuit when sending requests to
                       the server.

                       (Default = nnoovvcc; abbreviation = [nnoo]vv)

              [nnoo] iiggnnoorreettcc
                       Ignore packet truncation errors.

                       (Default = nnooiiggnnoorreettcc; abbreviation = [nnoo]iigg)

DDIIAAGGNNOOSSTTIICCSS
     If the lookup request was not successful, an error message is printed.
     Possible errors are:

     Timed out
            The server did not respond to a request after a certain amount of
            time (changed with ``sseett ttiimmeeoouutt==_v_a_l_u_e'') and a certain number of
            retries (changed with ``sseett rreettrryy==_v_a_l_u_e'').

     No response from server
            No name server is running on the server machine.

     No records
            The server does not have resource records of the current query
            type for the host, although the host name is valid.  The query
            type is specified with the ``sseett qquueerryyttyyppee'' command.

     Non-existent domain
            The host or domain name does not exist.

     Connection refused

     Network is unreachable
            The connection to the name or finger server could not be made at
            the current time.  This error commonly occurs with llss and ffiinnggeerr
            requests.

     Server failure
            The name server found an internal inconsistency in its database
            and could not return a valid answer.

     Refused
            The name server refused to service the request.

     Format error
            The name server found that the request packet was not in the prop-
            er format.  It may indicate an error in nnssllooookkuupp.

FFIILLEESS
     /etc/resolv.conf                  initial domain name and name server ad-
                                       dresses
     $HOME/.nslookuprc                 user's initial options
     /usr/share/misc/nslookup.help     summary of commands

EENNVVIIRROONNMMEENNTT



     HOSTALIASES      file containing host aliases
     LOCALDOMAIN      overrides default domain

SSEEEE AALLSSOO
     named(8),  resolver(3),  resolver(5);  RFC-1034, ``Domain Names -
     Concepts and Facilities''; RFC-1035, ``Domain Names - Implementation and
     Specification''.

AAUUTTHHOORR
     Andrew Cherenson

4th Berkeley Distribution        June 24, 1990                               6
