dig(ADMN) dig(ADMN) Name dig - send domain name query packets to name servers Syntax dig[@server]domain[<query-type>][<query-class>] [+<query-option>][-<dig-option>][%comment] Description The Domain Information Groper, dig, is a flexible command line tool which can be used to gather information from the Domain Name System servers. The dig tool has two modes: - simple interactive mode which makes a single query, and - batch which executes a query for each in a list of several query lines. All query options are accessible from the command line. The simple use of dig takes the following form: dig @server domain query-type query-class Options server may be either a domain name or a dot-notation Internet address. 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 (DNS) resolver. 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(SFF) for information on /etc/resolv.conf.] _________________________________________________________________________ WARNING Changing /etc/resolv.conf will affect the standard resolver 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; LOCALRES is specific to the dig resolver and is not referenced by the standard resolver. If the LOCALRES variable is not set, or if the file is not readable, then /etc/resolv.conf will be used. domain is the domain name for which you are requesting information. See OPTIONS [-x] for a convenient way to specify an inverse address query. query-type is the type of information (DNS query type) that you are requesting. If omitted, the default is "a" (TA = network-address). The following types will be recognized: a TA network address any TANY all/any information about specified domain mx TMX mail exchanger for the domain ns TNS name servers soa TSOA zone of authority record hinfo THINFO host information axfr TAXFR zone transfer (must ask an authoritative server) txt TTXT arbitrary number of strings (not yet supported by BIND) (See RFC 1035 for the complete list.) query-class is the network class requested in the query. If omitted, the default is "in" (CIN = Internet). The following classes are recognized: in CIN Internet class domain any CANY all/any class information (See RFC 1035 for the complete list.) _________________________________________________________________________ NOTE "any" can specify a class and/or a type of query: dig parse the first occurrence of "any" to mean query-type = TANY. To specify query-class = CANY you must either specify "any" twice, or set the query-class using the "-c" option (see below). _________________________________________________________________________ Other options %ignoredcomment Use "%" to include an argument which should 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 over- head of doing so, but still have the domain name on the command line as a reference. For example: dig @128.9.0.32 %venera.isi.edu mx isi.edu -<digoption> Use "-" to specify an option which affects the operation of dig. The following options are currently availableuaranteed to: -x dot-notation-address A convenient form to specify inverse address mapping: instead of "dig 32.0.9.128.in-addr.arpa" one can simply enter "dig -x 128.9.0.32". -f file A file for dig batch mode: the file contains a list of query speci- fications (that is, dig command lines) which are to be executed sequentially. Lines beginning with ``;'', ``#'', or ``\n'' are ignored. Other options may still appear on the 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 run- ning roughly in sync. The default value is zero. -p port Port Number: query a name server listening to a non-standard Port Number; the default value is 53. -P[ping-string] After the query returns, execute a ping(ADMN) command for a response time comparison. If the option "-Pping-string" is present, it will replace "ping -q" in the shell command. The last three lines of statistics will be printed for the command: ping -q -s 56 -c 3 servername -t query-type Specify the type of query: may specify either an integer value to be included in the type field or use the abbreviated mnemonic as discussed above (that is, mx = TMX). -c query-class Specify the class of query: may specify either an integer value to be included in the class field or use the abbreviated mnemonic as discussed above (that is, in = CIN). -envsav This flag specifies that the dig environment (defaults, print options, etc.), - after all of the arguments are parsed - should be saved to a file to become the default environment. This will be useful if you do not like the standard set of defaults and if you do not want to include a large number of options whenever dig is used. The environment will consist of resolver state variable flags, timeout values, and numbers of allowable retry attempts, as well as of the flags detailing the dig output contents (see below). If the shell environment variable LOCALDEF is set to the name of a file, this is where the default dig environment will be saved. If not, the file "DiG.env" will be created in the current working directory. _________________________________________________________________________ NOTE LOCALDEF is specific to the dig resolver and will not affect the operation of the standard resolver library. _________________________________________________________________________ Whenever dig is executed, it will look for "./DiG.env" or for the file specified by the shell environment variable LOCALDEF. If such a file exists and if it is readable, then the environment will be restored from this file before any arguments are parsed. -envset This flag will affect batch query runs only. When "-envset" is speci- fied on a line in a dig batch file, the dig environment following the arguments will be parsed; then these values will be used as the default environment for the duration of the batch file (or until the system finds another command line which specifies "-envset"). -[no]stick This flag will affect batch query runs only: it specifies that the dig environment (as read initially or set by the "-envset" switch) is to be restored before each query (line) in a dig batch file. The default value "-nostick" means that the dig environment should not stick; hence options specified on a single line in a dig batch file will remain in effect for subsequent lines (that is, they will not be restored to the ``sticky'' default). +<query-option> Use ``+'' to specify an option to be changed in the query packet or to change some dig output specifics. Many of these are the same parame- ters accepted by nslookup(TC). If an option requires a parameter, the format will be as follows: +keyword[=value] Most keywords can be abbreviated. Parsing of the ``+'' options is very simplistic -- a value must not be separated from its keyword by ``white space''. The following keywords are 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 # [4] time=# (ti) set timeout length to # seconds [4] [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 truncation errors [noi] [no]primary (pr) use/don't use primary server [nopr] [no]aaonly (aa) authoritative query only flag [noaa] [no]sort (sor) sort resource records [nosor] [no]cmd echo parsed arguments [cmd] [no]stats (st) print query statistics (RTT, etc) [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 hexadecimal/octal/decimal) pfand=# bitwise "and" print flags with # pfor=# bitwise "or" print flags with # The retry and time options will 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. _________________________________________________________________________ The pfset, pfand, and pfor options have been included to make the manipu- lation of the various print options less tedious. Here is a list of the currently defined meanings for the various print flag bits which may be combined (ANDed) to achieve various output formats. PRF_STATS 0x0001 RTT, query and server host, date, message size PRF_CLASS 0x0004 Resource record class information PRF_CMD 0x0008 echo the dig command line PRF_QUES 0x0010 questions section PRF_ANS 0x0020 answers section PRF_AUTH 0x0040 authoritative section PRF_ADD 0x0080 additional records section PRF_HEAD1 0x0100 RR section headers & counts PRF_HEAD2 0x0200 packet header flags PRF_TTLID 0x0400 Resource record Time-to-Live (ttl) PRF_HEADX 0x0800 basic header PRF_QUERY 0x1000 outgoing query packet PRF_REPLY 0x2000 reply packet PRF_SORT 0x8000 sort various response sections PRF_DEF 0x2ff9 default dig settings PRF_ZONE 0x24f9 default setting for zone transfer PRF_MIN 0xa930 minimalistic dig settings for (future) automated server testing When setting the print options and if you want to see information other than the statistics, you should choose to examine the outgoing (0x1000) packet type, the incoming (0x2000) packet type, or both packet types, as well as the specific sections of the packet(s) of particular interest to you. Details The dig tool requires a slightly modified version of the BIND resolver(SLIB) library to gather count and time statistics. Otherwise, it is a straight-forward effort of parsing arguments and setting appropriate parameters. The dig tool uses resolver routines resinit(,) resmkquery(,) ressend(;) it also accesses the res structure. It is possible to compile dig with the standard resolver library, but this procedure will change the dig output format, make the dig print options meaningless, and not gather RTT and packet count statistics. Files /etc/resolv.conf initial domain name and name server addresses ./DiG.env default save file for default options Environments LOCALRES file to use in place of /etc/resolv.conf LOCALDEF default environment file Notes dig does not exit consistently with an appropriate status when a problem occurs somewhere in the resolver. _________________________________________________________________________ NOTE Most of the common exit cases are handled. _________________________________________________________________________ When running in batch mode: If dig exits abnormally - and is not caught - the entire batch will abort; when such an event is trapped, dig simply will continue with the next query. See also nslookup(ADMN), resolver(SLIB), resolver(SFF), named(ADMN), ping(ADMN)