check-dns-from-wiki.sh

#!/bin/bash

# Scans the list of hosts and checks that
# DNS has a forward and reverse record for them
# Then compares the wiki host name with the PTR host name
# Generates a simple dokuwiki table
# runs in cron early every morning:
# check-dns-from-wiki.sh /data/wiki/data/pages/it/hostlist.txt > /data/wiki/data/pages/it/dnscheckresults.txt
# data is in a table, example:
# | [[:IT:hosts:test01.example.net]]                  | A test server, managed by XYZ corp  | contact this person in case of emergency                      |

HOST_LIST=$1

echo "====== DNS Check results ======"
echo
echo "^ Hostname                  ^ A Record ^ PTR Record ^ Records match? ^"

while IFS= read -r WIKI_LINE
do
  # cut everything before the first ]
  # then reverse the string
  # cut everything *after* the first :
  # then reverse the string (that's how you "cut" the last field in a string)
  HOST_NAME=$(echo "${WIKI_LINE}" | cut -d']' -f 1 | rev | cut -d':' -f 1 | rev)

  # default values
  A_RES="BAD"
  REV_RES="BAD"
  A_AND_REV_RES="BAD"

  ARESULT=$(dig "${HOST_NAME}" @192.168.151.4 +short)
  if [ -n "${ARESULT}" ]
  then
    A_RES="OK"
  else
    A_RES="BAD"
  fi

  if [ "${A_RES}" = "OK" ]
  then
    REVRESULT=$(dig -x "${ARESULT}" @192.168.151.4 +short)
    REV_RES="OK"

    if [ -n "${REVRESULT}" ]
    then
      REVRESULT_STRIPPED="${REVRESULT::-1}"
      if [ "${HOST_NAME}" = "${REVRESULT_STRIPPED}" ]
      then
        # echo "And A record matches PTR record!"
        A_AND_REV_RES="OK"
      else
        # echo "ERROR, A and PTR don't match!"
        A_AND_REV_RES="BAD"
      fi
    else
      # echo "${ARESULT} result is NULL"
      REV_RES="BAD"
    fi
  fi

  echo "|${HOST_NAME}   | ${A_RES}   | ${REV_RES}   | ${A_AND_REV_RES} |"

done < <(cat "${HOST_LIST}" | grep -E '^\| \[\[' | grep example)

echo
echo "----"
echo "Go back to [[IT::start|IT]]"