MAN page from Old RedHat 5.X bind-utils-4.9.7-1.i386.rpm

DIG

Section: User Commands (1)
Updated: August 30, 1990
Index

NAME

dig - send domain name query packets to name servers

SYNOPSIS

dig [@server]domain[<query-type>][<query-class>][+<query-option>][-<dig-option>][%comment]

DESCRIPTION

Dig (domain information groper) is a flexible command line toolwhich can be used to gather information from the DomainName System servers. Dig has two modes: simple interactive modewhich makes a single query, and batch which executes a query foreach in a list of several query lines. All query options areaccessible 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-notationInternet address. If this optional field is omitted, digwill attempt to use the default name server for your machine.

Note: If a domain name is specified, this will be resolvedusing the domain name system resolver (i.e., BIND). If yoursystem does not support DNS, you may have to specify adot-notation address. Alternatively, if there is a serverat your disposal somewhere, all that is required is that/etc/resolv.conf be present and indicate where the defaultname servers reside, so that server itself can beresolved. See resolver(5)for information on /etc/resolv.conf.(WARNING: Changing /etc/resolv.conf will affectthe standard resolver library and potentially severalprograms which use it.) As an option, the user may set theenvironment variable LOCALRES to name a file which is tobe used instead of /etc/resolv.conf (LOCALRES is specificto the dig resolver and not referenced by the standardresolver). If the LOCALRES variable is not set or the fileis not readable then /etc/resolv.conf will be used.

domain

is the domain name for which you are requesting information.See OPTIONS [-x] for convenient way to specify inverse addressquery.

query-type

is the type of information (DNS query type) thatyou are requesting. If omitted, the default is "a" (T_A = address).The following types are recognized:

a      T_A      network addressany    T_ANY    all/any information about specified domainmx     T_MX     mail exchanger for the domainns     T_NS     name serverssoa    T_SOA    zone of authority recordhinfo  T_HINFO  host informationaxfr   T_AXFR   zone transfer                 (must ask an authoritative server)txt    T_TXT    arbitrary number of strings

(See RFC 1035 for the complete list.)

query-class

is the network class requested in the query. Ifomitted, the default is "in" (C_IN = Internet).The following classes are recognized:

in     C_IN     Internet class domainany    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 ofquery. 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 setquery-class using "-c" option (see below).

OTHER OPTIONS

%ignored-comment

"%" is used to included an argument that is simply notparsed. This may be useful if running dig in batchmode. Instead of resolving every @server-domain-name ina list of queries, you can avoid the overhead of doingso, and still have the domain name on the command lineas a reference. Example:

dig @128.9.0.32 %venera.isi.edu mx isi.edu

-<dig option>

"-" is used to specify an option which effects theoperation of dig. The following options are currentlyavailable (although not guaranteed to be useful):

-x dot-notation-address

Convenient form to specify inverse address mapping.Instead of "dig 32.0.9.128.in-addr.arpa" one cansimply "dig -x 128.9.0.32".

-f file

File for dig batch mode. The file contains a listof query specifications (dig command lines) whichare to be executed successively. Lines beginningwith ';', '#', or '\n' are ignored. Other optionsmay still appear on command line, and will be ineffect for each batch query.

-T time

Time in seconds between start of successivequeries when running in batch mode. Can be usedto keep two or more batch dig commands runningroughly in sync. Default is zero.

-p port

Port number. Query a name server listening to anon-standard port number. Default is 53.

-P[ping-string]

After query returns, execute a ping(8)commandfor response time comparison. This ratherinelegantly makes a call to the shell. The lastthree lines of statistics is printed for thecommand:

ping -s server_name 56 3

If the optional "ping string" is present, itreplaces "ping -s" in the shell command.

-t query-type

Specify type of query. May specify either aninteger value to be included in the type fieldor use the abbreviated mnemonic as discussedabove (i.e., mx = T_MX).

-c query-class

Specify class of query. May specify either aninteger value to be included in the class fieldor use the abbreviated mnemonic as discussedabove (i.e., in = C_IN).

-envsav

This flag specifies that the dig environment(defaults, print options, etc.), afterall of the arguments are parsed, should be savedto a file to become the default environment.Useful if you do not like the standard set ofdefaults and do not desire to include alarge number of options each time dig is used.The environment consists of resolver statevariable flags, timeout, and retries as well asthe flags detailing dig output (see below).If the shell environment variable LOCALDEF is setto the name of a file, this is where the defaultdig environment 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 standardresolver library.

Each time dig is executed, it looks for "./DiG.env"or the file specified by the shell environment variableLOCALDEF. If such file exists and is readable, then theenvironment is restored from this filebefore any arguments are parsed.

-envset

This flag only affectsbatch query runs. When "-envset" isspecified on a line in a dig batch file,the dig environment after the arguments are parsed,becomes the default environment for the duration ofthe 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 initiallyor set by "-envset" switch) is to be restored before each query(line) in a dig batch file.The default "-nostick" means that the dig environmentdoes not stick, hence options specified on a single linein a dig batch file will remain in effect forsubsequent lines (i.e. they are not restored to the"sticky" default).

+<query option>

"+" is used to specify an option to be changed in thequery packet or to change dig output specifics. Manyof these are the same parameters accepted by nslookup(8).If an option requires a parameter, the form is asfollows:

+keyword[=value]

Most keywords can be abbreviated. Parsing of the "+"options is very simplistic --- a value must not beseparated from its keyword by white space. The followingkeywords 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 trunc. 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 [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 flagspfmin                set to minimal default print flagspfset=#              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 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)    endend

(Note: dig always uses a value of 1 for num_servers.)

DETAILS

Dig once required a slightly modified version of the BIND resolver(3)library. BIND's resolver has (as of BIND 4.9) been augmented to workproperly with Dig. Essentially, Dig is a straight-forward(albeit not pretty) effort of parsing arguments and setting appropriateparameters. Dig uses resolver routines res_init(), res_mkquery(),res_send() as well as accessing _res structure.

FILES

/etc/resolv.conf  initial domain name and name server
./DiG.env         default save file for default options

                 addresses

ENVIRONMENT

LOCALRES file to use in place of /etc/resolv.conf

LOCALDEF default environment file

AUTHOR

Steve Hotz hotzAATTisi.edu

ACKNOWLEDGMENTS

Dig uses functions from nslookup(8)authored by Andrew Cherenson.

BUGS

Dig has a serious case of "creeping featurism" -- the result ofconsidering several potential uses during it's development. It wouldprobably benefit from a rigorous diet. Similarly, the print flagsand granularity of the items they specify make evident theirrather ad hoc genesis.

Dig does not consistently exit nicely (with appropriate status)when a problem occurs somewhere in the resolver (NOTE: most of the commonexit cases are handled). This is particularly annoying when running inbatch mode. If it exits abnormally (and is not caught), the entirebatch aborts; when such an event is trapped, dig simplycontinues with the next query.

This document was created byman2html,using the manual pages.

DIG