DNS Monitor

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Best of luck,

 

-Colin

I will try that route.

 

 

Thank You.

I made an external monitor in perl. It sends a DNS request to a specific hostname. Hope this will help.

! /usr/bin/perl -w
 hostname
my ($domain)= "www.yahoo.fr";
my (@addrlist,$name,$altnames,$addrtype,$len,$packaddr);
my ($ip);
   hostname resolution 
  if (!(($name, $altnames, $addrtype, $len, @addrlist) = gethostbyname ($domain)))
  {
    return "DOWN";
  }
  else
  {
    return "UP";
  }

Regards,

Nicolas

Does that really work in testing the DNS service on the specified nodes? It looks to me like it makes a call to gethostbyname to resolve "www.yahoo.fr". This will use the local systems nameserver to resolve the name. So from what I can see this only tests your local DNS server as well as yahoo.fr's.

 

 

How it this testing DNS running on the nodes from a monitoring standpoint? Maybe I'm just missing something...

 

 

-Joe

Hi All,

 

 

I have a sample script, it work fine in V4.5.x but not in V9. I believe it miss out some perl module bcos when i try to run that script i get an error message look like this,

 

 

=======================================================

 

Can't locate Net/DNS.pm in @INC (@INC contains: /usr/lib/perl5/5.8.0/i386-linux- thread-multi /usr/lib/perl5/5.8.0 /usr/lib/perl5/site_perl/5.8.0/i386-linux-thre ad-multi /usr/lib/perl5/site_perl/5.8.0 /usr/lib/perl5/site_perl /usr/lib/perl5/ vendor_perl/5.8.0/i386-linux-thread-multi /usr/lib/perl5/vendor_perl/5.8.0 /usr/ lib/perl5/vendor_perl /usr/lib/perl5/5.8.0/i386-linux-thread-multi /usr/lib/perl 5/5.8.0 .) at ./dns_mon line 5.

 

BEGIN failed--compilation aborted at ./dns_mon line 5.

 

==============================================================

 

 

below is my sample script, pls give some advise if you think out something to make this work in V9.

 

===============================================================

 

!/usr/local/bin/perl

 

 

 

use strict;

 

use Net::DNS;

 

require 5.005;

 

 

 

my ($node, $port, @domain) = @ARGV;

 

 

 

Derive and untaint programname.

 

my $programname = '/' . $0;

 

$programname =~ m/^.*\/([^\/]+)$/;

 

$programname = $1;

 

 

 

$node =~ m/^(\d+\.\d+\.\d+\.\d+)$/;

 

$node = $1;

 

 

 

$port =~ m/^(\d+)$/;

 

$port = $1;

 

 

 

Process ID and file where it's to be stored. The format

 

is significant.

 

 

 

my $pidfile = "/var/run/$programname.$node..$port.pid";

 

my $pid = "$$";

 

 

 

Maintenence. Clean up any existing EAV.

 

 

 

if (-f $pidfile ) {

 

open(PID, "<$pidfile");

 

my $pid = ;

 

close(PID);

 

if ( $pid ) {

 

chomp $pid; $pid =~ m/^(\d+)$/; $pid = $1;

 

if ( $pid ) {

 

kill 9, $pid;

 

}

 

}

 

unlink($pidfile);

 

}

 

 

 

Create a new maintenence file.

 

 

 

open(PID, ">$pidfile");

 

print PID $pid, "\n";

 

close(PID);

 

 

 

Connect to the DNS server.

 

Perform A record lookup

 

my $res = Net::DNS::Resolver->new;

 

$res->nameservers($node);

 

my $ipquery = $res->search("@domain");

 

 

 

if (!($ipquery))

 

{

 

print STDERR "Failed to connect, ", $res->errorstring, "\n";

 

unlink($pidfile);

 

exit 1;

 

}

 

 

 

print "up\n";

 

 

 

Clean up.

 

unlink($pidfile);

 

exit 0;

 

 

===============================================================

 

regards