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087-the-dig-command.md

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The dig command

dig - DNS lookup utility

The dig is a flexible tool for interrogating DNS name servers. It performs DNS lookups and displays the answers that are returned from the name server(s) that were queried.

Examples:

  1. Dig is a network administration command-line tool for querying the Domain Name System.
dig google.com
  1. The system will list all google.com DNS records that it finds, along with the IP addresses.
dig google.com ANY

Syntax:

dig [server] [name] [type] [q-type] [q-class] {q-opt}
            {global-d-opt} host [@local-server] {local-d-opt}
            [ host [@local-server] {local-d-opt} [...]]

Additional Flags and their Functionalities:

domain    is in the Domain Name System
        q-class  is one of (in,hs,ch,...) [default: in]
        q-type   is one of (a,any,mx,ns,soa,hinfo,axfr,txt,...) [default:a]
                 (Use ixfr=version for type ixfr)
        q-opt    is one of:
                 -4                  (use IPv4 query transport only)
                 -6                  (use IPv6 query transport only)
                 -b address[#port]   (bind to source address/port)
                 -c class            (specify query class)
                 -f filename         (batch mode)
                 -k keyfile          (specify tsig key file)
                 -m                  (enable memory usage debugging)
                 -p port             (specify port number)
                 -q name             (specify query name)
                 -r                  (do not read ~/.digrc)
                 -t type             (specify query type)
                 -u                  (display times in usec instead of msec)
                 -x dot-notation     (shortcut for reverse lookups)
                 -y [hmac:]name:key  (specify named base64 tsig key)
        d-opt    is of the form +keyword[=value], where keyword is:
                 +[no]aaflag         (Set AA flag in query (+[no]aaflag))
                 +[no]aaonly         (Set AA flag in query (+[no]aaflag))
                 +[no]additional     (Control display of additional section)
                 +[no]adflag         (Set AD flag in query (default on))
                 +[no]all            (Set or clear all display flags)
                 +[no]answer         (Control display of answer section)
                 +[no]authority      (Control display of authority section)
                 +[no]badcookie      (Retry BADCOOKIE responses)
                 +[no]besteffort     (Try to parse even illegal messages)
                 +bufsize[=###]      (Set EDNS0 Max UDP packet size)
                 +[no]cdflag         (Set checking disabled flag in query)
                 +[no]class          (Control display of class in records)
                 +[no]cmd            (Control display of command line -
                                      global option)
                 +[no]comments       (Control display of packet header
                                      and section name comments)
                 +[no]cookie         (Add a COOKIE option to the request)
                 +[no]crypto         (Control display of cryptographic
                                      fields in records)
                 +[no]defname        (Use search list (+[no]search))
                 +[no]dnssec         (Request DNSSEC records)
                 +domain=###         (Set default domainname)
                 +[no]dscp[=###]     (Set the DSCP value to ### [0..63])
                 +[no]edns[=###]     (Set EDNS version) [0]
                 +ednsflags=###      (Set EDNS flag bits)
                 +[no]ednsnegotiation (Set EDNS version negotiation)
                 +ednsopt=###[:value] (Send specified EDNS option)
                 +noednsopt          (Clear list of +ednsopt options)
                 +[no]expandaaaa     (Expand AAAA records)
                 +[no]expire         (Request time to expire)
                 +[no]fail           (Don't try next server on SERVFAIL)
                 +[no]header-only    (Send query without a question section)
                 +[no]identify       (ID responders in short answers)
                 +[no]idnin          (Parse IDN names [default=on on tty])
                 +[no]idnout         (Convert IDN response [default=on on tty])
                 +[no]ignore         (Don't revert to TCP for TC responses.)
                 +[no]keepalive      (Request EDNS TCP keepalive)
                 +[no]keepopen       (Keep the TCP socket open between queries)
                 +[no]mapped         (Allow mapped IPv4 over IPv6)
                 +[no]multiline      (Print records in an expanded format)
                 +ndots=###          (Set search NDOTS value)
                 +[no]nsid           (Request Name Server ID)
                 +[no]nssearch       (Search all authoritative nameservers)
                 +[no]onesoa         (AXFR prints only one soa record)
                 +[no]opcode=###     (Set the opcode of the request)
                 +padding=###        (Set padding block size [0])
                 +[no]qr             (Print question before sending)
                 +[no]question       (Control display of question section)
                 +[no]raflag         (Set RA flag in query (+[no]raflag))
                 +[no]rdflag         (Recursive mode (+[no]recurse))
                 +[no]recurse        (Recursive mode (+[no]rdflag))
                 +retry=###          (Set number of UDP retries) [2]
                 +[no]rrcomments     (Control display of per-record comments)
                 +[no]search         (Set whether to use searchlist)
                 +[no]short          (Display nothing except short
                                      form of answers - global option)
                 +[no]showsearch     (Search with intermediate results)
                 +[no]split=##       (Split hex/base64 fields into chunks)
                 +[no]stats          (Control display of statistics)
                 +subnet=addr        (Set edns-client-subnet option)
                 +[no]tcflag         (Set TC flag in query (+[no]tcflag))
                 +[no]tcp            (TCP mode (+[no]vc))
                 +timeout=###        (Set query timeout) [5]
                 +[no]trace          (Trace delegation down from root [+dnssec])
                 +tries=###          (Set number of UDP attempts) [3]
                 +[no]ttlid          (Control display of ttls in records)
                 +[no]ttlunits       (Display TTLs in human-readable units)
                 +[no]unexpected     (Print replies from unexpected sources
                                      default=off)
                 +[no]unknownformat  (Print RDATA in RFC 3597 "unknown" format)
                 +[no]vc             (TCP mode (+[no]tcp))
                 +[no]yaml           (Present the results as YAML)
                 +[no]zflag          (Set Z flag in query)
        global d-opts and servers (before host name) affect all queries.
        local d-opts and servers (after host name) affect only that lookup.
        -h                           (print help and exit)
        -v                           (print version and exit)