Dig Commands

Look up A record example.com as seen by 8.8.8.8 nameserver
dig @8.8.8.8 exampe.com

Show the MX record for a yahoo domain
dig yahoo.com MX

Show the TTL for a given domain
dig imagescape.com TTL

Show the TXT record for an yahoo domain
dig yahoo.com TXT

Show only the answer

dig yahoo.com +nocomments +noquestion +noauthority +noadditional +nostats

All Records

dig @8.8.8.8 imagescape.com ANY +noall +answer

Reverse Lookup

dig -x 198.178.132.10

Nice output that looks like the domain record

dig @ns.imagescape.com imagescape.com any +multiline +noall +answer

Find the authoritative nameserver for a domain:

dig -t ns imagescape.com +short

Find the SOA of the domain:
dig joejasinski.com soa +noall +answer


dig @ns1.linode.com joejasinski.com soa

; <<>> DiG 9.10.3-P4-Ubuntu <<>> @ns1.linode.com joejasinski.com soa
; (2 servers found)
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- 64217="" id:="" noerror="" opcode:="" p="" query="" status:="">;; flags: qr aa rd; QUERY: 1, ANSWER: 1, AUTHORITY: 5, ADDITIONAL: 11
;; WARNING: recursion requested but not available

;; ANSWER SECTION:
joejasinski.com. 86400 IN SOA ns1.linode.com. joe\.jasinski.gmail.com. 2014092859 14400 14400 1209600 86400

The presence "aa" indicates if the nameserver is the authoritative server.

The "2014092859" is the serial

Download a zone file (zone transfer):
dig axfr domain.com


Common Options:
  +short  = show only the results
  +[no]comments = show/hide the comments
  +[no]question = show/hide the question section
  +[no]authority = show/hide the authority section
  +[no]stats = show/hide the stats section
  +[no]answer = show/hide the answer section
  +[no]all = show/hide everything

https://neverendingsecurity.wordpress.com/2015/04/13/dig-commands-cheatsheet/

https://www.madboa.com/geek/dig/

Nice articles:

Commands
http://anouar.adlani.com/2011/12/useful-dig-command-to-troubleshot-your-domains.html

Create DNS Slave
http://www.microhowto.info/howto/configure_bind_as_a_slave_dns_server.html

Simple Network Test Script

This is a simple script to log network outages on a local network

root@ubuntu:/mnt/root/usr/local/bin# more lifeline
#!/bin/bash

PING='/bin/ping'
EXTHOST1='www.google.com'
EXTHOST2='sun.iwu.edu'
INTHOST='192.168.1.1'
LOG='/var/log/network_outages'
WAITTIME=120

echo "NETWORK STATUS SCRIPT: Started " `date` >> $LOG
while [ 1=1 ]
do
   dater=`date +%Y.%m.%d-%H.%M.%S`
   $PING -q -c1 $EXTHOST1
   ret=$?
   echo "RET: $ret"
   if [ $ret -ne 0 ]
   then
     echo "EXTERNAL_PING(1): outage detected $dater" >> $LOG
   fi

   dater=`date +%Y.%m.%d-%H.%M.%S`
   $PING -q -c1 $EXTHOST2
   ret=$?
   echo "RET: $ret"
   if [ $ret -ne 0 ]
   then
     echo "EXTERNAL_PING(2): outage detected $dater" >> $LOG
   fi

   $PING -q -c1 $INTHOST
   ret=$?
   echo "RET: $ret"
   if [ $ret -ne 0 ]
   then
     echo "INTERNAL_PING: outage detected $dater" >> $LOG
   fi

   sleep $WAITTIME
done