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);