Dig Networking Utility
The dig networking utility on Unix-like systems provides technical DNS information for domains. Here’s the help options for dig usage:
root@thatcommunity [/home]# dig -h
Usage: dig [@global-server] [domain] [q-type] [q-class] {q-opt}
{global-d-opt} host [@local-server] {local-d-opt}
[ host [@local-server] {local-d-opt} [...]]
Where: 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:
-x dot-notation (shortcut for reverse lookups)
-i (use IP6.INT for IPv6 reverse lookups)
-f filename (batch mode)
-b address[#port] (bind to source address/port)
-p port (specify port number)
-t type (specify query type)
-c class (specify query class)
-k keyfile (specify tsig key file)
-y name:key (specify named base64 tsig key)
-4 (use IPv4 query transport only)
-6 (use IPv6 query transport only)
-m (enable memory usage debugging)
d-opt is of the form +keyword[=value], where keyword is:
+[no]vc (TCP mode)
+[no]tcp (TCP mode, alternate syntax)
+time=### (Set query timeout) [5]
+tries=### (Set number of UDP attempts) [3]
+retry=### (Set number of UDP retries) [2]
+domain=### (Set default domainname)
+bufsize=### (Set EDNS0 Max UDP packet size)
+ndots=### (Set NDOTS value)
+[no]search (Set whether to use searchlist)
+[no]defname (Ditto)
+[no]recurse (Recursive mode)
+[no]ignore (Don't revert to TCP for TC responses.)
+[no]fail (Don't try next server on SERVFAIL)
+[no]besteffort (Try to parse even illegal messages)
+[no]aaonly (Set AA flag in query (+[no]aaflag))
+[no]adflag (Set AD flag in query)
+[no]cdflag (Set CD flag in query)
+[no]cl (Control display of class in records)
+[no]cmd (Control display of command line)
+[no]comments (Control display of comment lines)
+[no]question (Control display of question)
+[no]answer (Control display of answer)
+[no]authority (Control display of authority)
+[no]additional (Control display of additional)
+[no]stats (Control display of statistics)
+[no]short (Disable everything except short
form of answer)
+[no]ttlid (Control display of ttls in records)
+[no]all (Set or clear all display flags)
+[no]qr (Print question before sending)
+[no]nssearch (Search all authoritative nameservers)
+[no]identify (ID responders in short answers)
+[no]trace (Trace delegation down from root)
+[no]dnssec (Request DNSSEC records)
+[no]multiline (Print records in an expanded format)
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)
For example, if I dig thatnetwork.com, it returns these results:
root@thatcommunity [/home]# dig thatnetwork.com
; <<>> DiG 9.3.6-P1-RedHat-9.3.6-4.P1.el5_4.2 <<>> thatnetwork.com
;; global options: printcmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 4448
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 0
;; QUESTION SECTION:
;thatnetwork.com. IN A
;; ANSWER SECTION:
thatnetwork.com. 3600 IN A 64.34.165.234
;; Query time: 169 msec
;; SERVER: 216.187.125.131#53(216.187.125.131)
;; WHEN: Tue Nov 30 14:13:23 2010
;; MSG SIZE rcvd: 49
The response shows you the DNS information for thatnetwork.com.
