Updated nscheck to be more resilient. In some cases, nscheck would incorrectly believe that the parent TLD was the root zone, ie it would assume that maff.com is a subdomain and "com" itself is the root zone

nscheck

@@ -1,35 +1,27 @@
-#!/usr/bin/env bash
+#!/usr/local/bin/bash
 #nscheck.sh - Simple script to do fairly good DNS diagnostics, to determine: Failing/slow nameservers, result inconsistency and so on.
 
+# Copyright (c) 2012, Matthew Connelly
+# All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:
+# - Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.
+# - Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.
+# - Neither the name of the software nor the names of its contributors may be used to endorse or promote products derived from this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
 #TODO
 # - Handle multiple results for single record names (DNS round-robin)
-# - Use getopt for better commandline arg parsing
 
 #Configurables
 TIMEOUT=1
 
 #Binary locations
-DIG_BIN="$(command -v dig)"
+DIG_BIN="/usr/bin/dig"
-if [ $? -ne 0 -o -z "$DIG_BIN" ]; then
-	echo "Error: 'dig' cannot be found. Please ensure you have the relevant package for 'dig' installed."
-	exit 1
-fi
-
-#Functions
-function usage () {
-	echo "nscheck 0.1: Bash script to do DNS diagnosis.
-NOTE: This script will not, at present, function properly for DNS queries which result in more than one record of the same type (ie, DNS round robins)
-
-Usage: nscheck [-4|-6] DNS.ENTITY
-nscheck -m: Show machine-parseable output (keypairs indicating nameserver responsiveness)
-nscheck -h: Show this usage.
-nscheck -4: Use IPv4 [Default].
-nscheck -6: Use IPv6."
-}
 
 #Internal variables
 DIG_RECORD_TYPE="A"
-HUMAN_READABLE=1
 ZONE=""
 if [ "$1" == "-6" ]; then
 	DIG_RECORD_TYPE="AAAA"
@@ -37,33 +29,33 @@ if [ "$1" == "-6" ]; then
 elif [ "$1" == "-4" ]; then
 	ZONE=$2
 elif [ "$1" == "-h" ]; then
-	usage
+	echo "nscheck 0.1: Bash script to do DNS diagnosis.
+NOTE: This script will not, at present, function properly for DNS queries which result in more than one record of the same type (ie, DNS round robins)
+
+Usage: nscheck [-4|-6] DNS.ENTITY
+nscheck -h: Show this usage.
+nscheck -4: Use IPv4 [Default].
+nscheck -6: Use IPv6."
 	exit 0
-elif [ "$1" == "-m" ]; then
-	HUMAN_READABLE=0
-	ZONE=$2
 else
 	ZONE=$1
 fi
-if [ -z "$ZONE" ]; then
-	usage
-	exit 1
-fi
 DOMAIN=$ZONE
-MACHINE_SEPARATOR=";"
 IPS_REPORTED=""
 NS_REPORTED=""
 FAILED_NS=""
 IPS_CHECKED=""
 SUCCESS_OUT="NS | NS-IP | NS-REVERSE | IP | REVERSE"
 FAIL_OUT="NS | NS-IP | NS-REVERSE"
-MACHINE_OUT=""
 
 #Because this is a DNS debugging script, we don't rely on a domain's nameservers themselves for a list of nameservers. Instead, we query root and TLD nameservers.
-#We could in future use WHOIS data to get nameservers.
 
 #First we make sure we're querying the nameservers for the actual domain and not a subdomain. Also; remove trailing dot.
-OUT=$($DIG_BIN $ZONE SOA|grep "^;; AUTH" -A1|tail -n1|awk '{print $1}'|sed -e 's/.$//g')
+OUT=$($DIG_BIN $ZONE SOA|grep "^;; ANSWER" -A1|tail -n1|awk '{print $1}'|sed -e 's/.$//g')
+if [ -z "$OUT" ]; then
+	#Try again.
+	OUT=$($DIG_BIN $ZONE SOA|grep "^;; AUTH" -A1|grep "SOA"|tail -n1|awk '{print $1}'|sed -e 's/.$//g')
+fi
 if [ -z "$OUT" ]; then
 	#Try again.
 	OUT=$($DIG_BIN $ZONE SOA|grep "^;; ANSWER" -A6|grep "SOA"|tail -n1|awk '{print $1}'|sed -e 's/.$//g')
@@ -75,7 +67,7 @@ for ns in $($DIG_BIN +short $ZONE NS); do
 	if [[ $NS_REPORTED != *"$ns"* ]]; then
 		NS_REPORTED="$NS_REPORTED$ns "
 	fi
-	for ip in $($DIG_BIN +short $ns); do
+	for ip in $($DIG_BIN +short $ns $DIG_RECORD_TYPE); do
 		if [[ $IPS_CHECKED != *"$ip"* ]]; then
 			IPS_CHECKED="$IPS_CHECKED $ip"
 			#We need to use tail here in order to stop dig from being fucking retarded and providing a cname as well as the result
@@ -101,21 +93,13 @@ for ns in $($DIG_BIN +short $ZONE NS); do
 				fi
 				SUCCESS_OUT="$SUCCESS_OUT
 $ns | $ip | $REVERSE | $OUT | $REVOUT"
-				MACHINE_OUT="$MACHINE_OUT$ip${MACHINE_SEPARATOR}1
-"
 			else
 				FAIL_OUT="$FAIL_OUT
 $ns | $ip | $REVERSE"
-				MACHINE_OUT="$MACHINE_OUT$ip${MACHINE_SEPARATOR}0
-"
 			fi
 		fi
 	done
 done
-if [ $HUMAN_READABLE -eq 0 ]; then
-	echo -n "$MACHINE_OUT"|sort -n
-	exit
-fi
 if [[ $ZONE != $DOMAIN ]]; then
 	echo "Found root zone for $DOMAIN: $ZONE"
 fi