dig [@server] domain [<query-type>] [<query-class>] [+<query-option>] [-<dig-option>] [%comment]
Dig (domain information groper) is a flexible command line tool which can be used to gather information from the Domain Name System servers. Dig has two modes: simple interactive mode for a single query, and batch mode which executes a query for each in a list of several query lines. All query options are accessible from the command line. The usual simple use of dig will take the form: dig @server domain query-type query-class where: server may be either a domain name or a dot-notation Internet ad dress. If this optional field is omitted, dig will attempt to use the default name server for your machine. Note: If a domain name is specified, this will be resolved using the domain name system resolver (i.e., BIND). If your system does not support DNS, you may have to specify a dot- notation address. Alternatively, if there is a server at your disposal somewhere, all that is required is that /etc/resolv.conf be present and indicate where the default name servers reside, so that server itself can be resolved. See resolver(5) for information on /etc/resolv.conf. WARNING: Changing /etc/resolv.conf will affect both the standard re solver library and (potentially) several programs which use it. As an option, the user may set the environment variable LOCALRES to name a file which is to be used instead of /etc/resolv.conf standard resolver (LOCALRESis specific to the dig resolver and is not referenced by the). If the LOCALRES variable is not set or the specified file is not readable, then /etc/resolv.conf will be used. domain is the domain name for which you are requesting information. See the -x option (documented in the OTHER OPTIONS subsection of this section) for convenient way to specify inverse ad dress query. query-type is the type of information (DNS query type) that you are re questing. If omitted, the default is ``a'' (T_A = address). The following types are recognized: a T_A network address any T_ANY all/any information about specified domain mx T_MX mail exchanger for the domain ns T_NS name servers soa T_SOA zone of authority record hinfo T_HINFO host information axfr T_AXFR zone transfer (must ask an authoritative in C_IN Internet class domain any C_ANY all/any class information (See RFC 1035 for the complete list.) Note: ``Any'' can be used to specify a class and/or a type of query. Dig will parse the first occurrence of ``any'' to mean query-type = T_ANY. To specify query-class = C_ANY, you must either specify ``any'' twice, or set query-class using the -c option (see below). OTHER OPTIONS %ignored-comment ``%'' is used to included an argument that is simply not parsed. This may be useful if running dig in batch mode. Instead of resolving every @server-domain-name in a list of queries, you can avoid the overhead of doing so, and still have the domain name on the command line as a reference. Ex ample: dig @184.108.40.206 %venera.isi.edu mx isi.edu -<dig option> ``-'' is used to specify an option which affects the opera tion of dig. The following options are currently available (although not guaranteed to be useful): -x dot-notation-address Convenient form to specify inverse address map ping. Instead of ``dig 220.127.116.11.in- addr.arpa'', one can simply ``dig -x 18.104.22.168''. -f file File for dig batch mode. The file contains a list of query specifications ( dig command lines) which are to be executed successively. Lines be ginning with `;', `#', or `\n' are ignored. Oth er options may still appear on command line, and will be in effect for each batch query. -T time Time in seconds between start of successive queries when running in batch mode. Can be used to keep two or more batch dig commands running roughly in sync. Default is zero. -p port Port number. Query a name server listening to a non-standard port number. Default is 53. -P[ping-string] After query returns, execute a ping(8) command for response time comparison. This rather unele gantly makes a call to the shell. The last three lines of statistics is printed for the command: -c query-class Specify class of query. May specify either an in teger value to be included in the class field or use the abbreviated mnemonic as discussed above (i.e., in = C_IN). -k keydir:keyname Sign the query with the TSIG key named keyname that is in the directory keydir. -envsav This flag specifies that the dig environment (de faults, print options, etc.), after all of the arguments are parsed, should be saved to a file to become the default environment. This is use ful if you do not like the standard set of de faults and do not desire to include a large num ber of options each time dig is used. The envi ronment consists of resolver state variable flags, timeout, and retries as well as the flags detailing dig output (see below). If the shell environment variable LOCALDEF is set to the name of a file, this is where the default dig environ ment is saved. If not, the file ``DiG.env'' is created in the current working directory. Note: LOCALDEF is specific to the dig resolver, and will not affect operation of the standard re solver library. Each time dig is executed, it looks for ``./DiG.env'' or the file specified by the shell environment variable LOCALDEF. If such file ex ists and is readable, then the environment is re stored from this file before any arguments are parsed. -envset This flag only affects batch query runs. When ``-envset'' is specified on a line in a dig batch file, the dig environment after the arguments are parsed becomes the default environment for the duration of the batch file, or until the next line which specifies ``-envset''. -[no] stick This flag only affects batch query runs. It specifies that the dig environment (as read ini tially or set by ``-envset'' switch) is to be re stored before each query (line) in a dig batch file. The default ``-nostick'' means that the dig environment does not stick, hence options specified on a single line in a dig batch file will remain in effect for subsequent lines (i.e. they are not restored to the ``sticky'' default). currently available: Keyword Abbrev. Meaning [default] [no] debug (deb) turn on/off debugging mode [deb] [no] d2 turn on/off extra debugging mode [nod2] [no] recurse (rec) use/don't use recursive lookup [rec] retry=# (ret) set number of retries to #  time=# (ti) set timeout length to # seconds  [no] ko keep open option (implies vc) [noko] [no] vc use/don't use virtual circuit [novc] [no] defname (def) use/don't use default domain name [def] [no] search (sea) use/don't use domain search list [sea] domain=NAME (do) set default domain name to NAME [no] ignore (i) ignore/don't ignore trunc. errors [noi] [no] primary (pr) use/don't use primary server [nopr] [no] aaonly (aa) authoritative query only flag [noaa] [no] cmd echo parsed arguments [cmd] [no] stats (st) print query statistics [st] [no] Header (H) print basic header [H] [no] header (he) print header flags [he] [no] ttlid (tt) print TTLs [tt] [no] cl print class info [nocl] [no] qr print outgoing query [noqr] [no] reply (rep) print reply [rep] [no] ques (qu) print question section [qu] [no] answer (an) print answer section [an] [no] author (au) print authoritative section [au] [no] addit (ad) print additional section [ad] pfdef set to default print flags pfmin set to minimal default print flags pfset=# set print flags to # (# can be hex/octal/decimal) pfand=# bitwise and print flags with # pfor=# bitwise or print flags with # The retry and time options affect the retransmission strategy used by the resolver library when sending datagram queries. The algorithm is as follows: for i = 0 to retry - 1 for j = 1 to num_servers send_query wait((time * (2**i)) / num_servers) end end (Note: dig always uses a value of 1 for ``num_servers''.) DETAILS tions, above.
/etc/resolv.conf initial domain name and name server addresses ./DiG.env default save file for default options
named(8), resolver(3), resolver(5), nslookup(8).
Steve Hotz email@example.com
Dig uses functions from nslookup(8) authored by Andrew Cherenson.
Dig has a serious case of "creeping featurism" -- the result of consider ing several potential uses during it's development. It would probably benefit from a rigorous diet. Similarly, the print flags and granularity of the items they specify make evident their rather ad hoc genesis. Dig does not consistently exit nicely (with appropriate status) when a problem occurs somewhere in the resolver (NOTE:most of the common exit cases are handled). This is particularly annoying when running in batch mode. If it exits abnormally (and is not caught), the entire batch aborts; when such an event is trapped, dig simply continues with the next query. 4th Berkeley Distribution August 30, 1990 5
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