File dnswalk-unpingable.patch of Package dnswalk

Description: Patch to allow unpingable nameserversto be ignored if queries to them time out.
Author: Paul Wayper
Origin: other, https://sourceforge.net/p/dnswalk/patches/4/
Bug:
Last-Update: 2010-11-25

This patch gives dnswalk the -t option, which allows unpingable nameservers to be ignored if queries to them time out.
Put another way: if a name server is returning 'query timed out', the -t option then allows you to ignore this nameserver if it is also unpingable.
I coded this option when we had a data centre move and some of our nameservers were down. Since we run Nagios we already knew the servers were down...

#--- dnswalk-20101125-pjw 2010-11-25 11:20:50.000000000 +1100
#+++ dnswalk 2010-11-25 11:36:17.000000000 +1100
#@@ -17,12 +17,14 @@
# # dnswalk has been run previously.)
# # -F Enable "facist" checking. (See man page)
# # -l Check lame delegations
#+# -t Ignore query timeouts on unpingable nameservers
#
# use Getopt::Std;
# use IO::Socket;
# use Net::DNS;
#+use Net::Ping;
#
#-getopts("D:rfiadmFl");
#+getopts("D:rfiadmFlt");
#
# $num_error{'FAIL'}=0; # failures to access data
# $num_error{'WARN'}=0; # questionable data
#@@ -403,10 +405,15 @@
# }
# $soa_req = $res->send($packet);
# unless (defined($soa_req)) {
#- &printerr("FAIL",
#- "Cannot get SOA record for $zone from $nameserver (lame?): ".
#- $res->errorstring ."\n");
#- return;
#+ if ($res->errorstring eq 'query timed out' and $opt_t) {
#+ # If we can't ping the machine, don't warn about the query timing out.
#+ my $p = Net::Ping->new('icmp');
#+ return unless $p->ping($nameserver, 4);
#+ }
#+ &printerr("FAIL",
#+ "Cannot get SOA record for $zone from $nameserver (lame?): ".
#+ $res->errorstring ."\n");
#+ return;
# }
# &printerr("BAD", "$zone NS $nameserver: lame NS delegation\n")
# unless ($soa_req->header->aa);
--- dnswalk.orig	2018-12-27 12:34:54.981105029 +0100
+++ dnswalk	2018-12-27 12:37:59.847476898 +0100
@@ -17,14 +17,16 @@
 #          dnswalk has been run previously.)
 #    -F    Enable "facist" checking.  (See man page)
 #    -l    Check lame delegations
+#    -t    Ignore query timeouts on unpingable nameservers
 
 use Getopt::Std;
 use IO::Socket;
 use Net::DNS;
 use Net::IP;
+use Net::Ping;
 use Socket6;
 
-getopts("D:rfiadmFl");
+getopts("D:rfiadmFlt");
 
 $num_error{'FAIL'}=0;		# failures to access data
 $num_error{'WARN'}=0;		# questionable data
@@ -152,9 +154,15 @@
     my ($packet) = new Net::DNS::Packet($zone, "SOA", "IN");
     my ($soa_req) = $res->send($packet);
     unless (defined($soa_req)) {
-	&printerr("FAIL", "Cannot get SOA record for $zone:" . 
-		  $res->errorstring . "\n");
-	return "";
+	if ($res->errorstring eq 'query timed out' and $opt_t) {
+	# If we can't ping the machine, don't warn about the query timing out.
+	my $p = Net::Ping->new('icmp');
+	return unless $p->ping($nameserver, 4);
+	}
+	&printerr("FAIL",
+	"Cannot get SOA record for $zone from $nameserver (lame?): ".
+	$res->errorstring ."\n");
+	return;
     }
     unless (($soa_req->header->ancount >= 1) && 
 	   (($soa_req->answer)[0]->type eq "SOA")) {