Today, I thought I'd put out another script that might be helpful to at least a few of us out there. As you may recall, in an earlier post we went over a script that checked network hosts' ports non-maliciously. This is a combination of that with a little something extra.
Okay, there are a few extra elements here. The main function of the script is to check that all the servers in the @hostnames array are up and running. This is done as simply as possible, using ping. The second thing it checks is that FTP is up and running on all hosts (We're assuming that you're running this from a box on your network that has access - through firewalls, router acl's and whatnot - to all of the servers listed). Thirdly, it looks at a subset of servers that you define within the script, and tries to determine if HTTP is up and running.
This script is slightly more complicated than the other, as it uses the Perl Socket and CGI modules and also makes use of signal handling (Touched on in more detail in this previous post. Finally, we do some while loop tagging to control the flow.
Of course, this script can be modified easily to include other system checks. I wrote this to get a quick feel for the health of the network and get an easy read on any problems at whatever time I chose to open the page in my web browser.
Hopefully, you'll find this useful. I've commented the script near all the parts that can/should be edited (IN CAPITALS FOR EASE OF VIEWING). Otherwise, it's pretty much self explanatory.
Cheers,
This work is licensed under a
Creative Commons Attribution-Noncommercial-Share Alike 3.0 United States License#!/usr/bin/perl
#
# whatup.cgi - 2008 - Mike Golvach - eggi@comcast.net
#
# Creative Commons Attribution-Noncommercial-Share Alike 3.0 United States License
#
use CGI;
use Socket;
require 5.002;
# FILL THIS ARRAY WITH ALL THE HOSTNAMES YOU WANT TO MONITOR
@hostnames = qw(host1 host2 host3 hosta hostb hostc hostn);
foreach $pingable_host (@hostnames) {
$answer=`/usr/sbin/ping $pingable_host 1 1`;
if ( $answer=~ /alive/ ) {
$is_it_up_or_not[$a] = 1;
$a++;
} else {
$is_it_up_or_not[$a] = 0;
$a++;
}
}
use CGI;
$whatup_cgi = new CGI;
@ports = qw(21 80);
$date = `date`;
print $whatup_cgi->header();
print "<html><head><meta HTTP-EQUIV=\"REFRESH\" CONTENT=\"300; URL=/whatup.cgi\"><title>What's Up?</title></head>\n";
print "<body BGCOLOR=\"#000000\" TEXT=\"#00FF00\" LINK=\"#FFFF00\" VLINK=\"#FF0000\" ALINK=\"#BECD8C\">\n";
print "<p>\n";
print "<br><hr><br>\n";
print "<p>\n";
print "<center><FONT COLOR=\"#FF0000\"><H3>Your Immediate Guide to What's Up On Our Network!</h3></FONT></center>\n";
print "<center><FONT COLOR=\"#BECD8C\"><H4>$date</h4></FONT></center>\n";
print "<p>\n";
print "<br><hr><br>\n";
print "<p>\n";
$b=0;
$c=0;
$SIG{'ALRM'} = 'next_goround';
OUTER: foreach $host (@hostnames) {
if ( $is_it_up_or_not[$b] ) {
print "<hr>\n";
print "<h3><font color=\"#BECD8C\">$host is Up!</font></h3>";
} else {
print "<hr>\n";
print "<h3><font color=\"#FF0000\">$host is Down!</font></h3>";
}
print "<ul>";
$CONNECTION_PORT = "NEXT_UP_IS${c}SOCK";
# IN THE BELOW IF STATEMENT, USE REGULAR EXPRESSIONS TO MATCH ALL HOST NAMES
# THAT YOU WANT TO BE CHECKED FOR HTTP. ALL HOSTS ARE CHECKED FOR FTP
if ( $host=~ /host[1-3]/ || $host=~ /host[ab]/ ) {
foreach $portno (@ports) {
$port = $portno;
if ($port =~ /\D/) {
$port = getservbyname($port, 'tcp');
}
$iaddr = inet_aton($host);
$paddr = sockaddr_in($port, $iaddr);
$proto = getprotobyname('tcp');
socket($CONNECTION_PORT, PF_INET, SOCK_STREAM, $proto);
if ( $is_it_up_or_not[$b] ) {
connect($CONNECTION_PORT, $paddr) unless alarm 10;
if ( $success_or_failure ) {
next;
}
alarm 0;
}
if ($port == 21 && ! $success_or_failure ) {
$portname = "FTP";
if ( $is_it_up_or_not[$b] ) {
$create_socket = send($CONNECTION_PORT, "user anonymous username\@xyz.com", 40) unless alarm 10;
alarm 0;
}
} else {
$portname = "HTTP";
if ( $is_it_up_or_not[$b] ) {
$create_socket = send($CONNECTION_PORT, "GET /index.html HTTP/1.0", 40) unless alarm 10;
alarm 0;
}
}
close($CONNECTION_PORT);
if ( ! $is_it_up_or_not[$b] && ! $success_or_failure ) {
print "<li><h3><font color=\"#FF0000\">$portname is Down!</h3></font></ul>";
$b++;
next OUTER;
}
if ($create_socket) {
print "<li><h3><font color=\#FFFF00\">$portname is Up!</h3></font>";
} else {
print "<li><h3><font color=\"#FF0000\">$portname is Down!</h3></font>";
}
$c++;
$success_or_failure = 0;
}
print "</ul>\n";
} else {
$port = 21;
if ($port =~ /\D/) {
$port = getservbyname($port, 'tcp');
}
$iaddr = inet_aton($host);
$paddr = sockaddr_in($port, $iaddr);
$proto = getprotobyname('tcp');
socket($CONNECTION_PORT, PF_INET, SOCK_STREAM, $proto);
if ( $is_it_up_or_not[$b] ) {
connect($CONNECTION_PORT, $paddr) unless alarm 10;
alarm 0;
}
if ( $is_it_up_or_not[$b] && ! $success_or_failure ) {
$create_socket = send($CONNECTION_PORT, "user anonymous username\@xyz.com", 40) unless alarm 10;
alarm 0;
}
$portname = "FTP";
close($CONNECTION_PORT);
if ( ! $is_it_up_or_not[$b] && ! $success_or_failure ) {
print "<li><h3><font color=\"#FF0000\">$portname is Down!</h3></font></ul>";
$b++;
next OUTER;
}
if ($create_socket) {
print "<li><h3><FONT COLOR=\"#FFFF00\">$portname is Up!</h3></font>";
} else {
print "<li><h3><font color=\"#FF0000\">$portname is Down!</h3></font>";
}
print "</ul>\n";
$c++;
$success_or_failure = 0;
}
$b++;
}
$whatup_cgi->end_html();
sub next_goround {
close($CONNECTION_PORT);
return $success_or_failure = 1;
}
, Mike
linux unix internet technology
Wednesday, January 2, 2008
A Simple CGI Script To Check Network Hosts' Status
Tuesday, December 4, 2007
Solving Network Issues at the PROM Level
As you may recall, in a previous post we looked at how to disable Sun network devices at the PROM level. In this post we're going to look at the the flipside, somewhat, of that coin.
This situation can occur quite frequently if you're building boxes on a network where the folks who run the switches and routers insist on "pinning" their ports to "100 full" or "1000 full" (speed - duplex) rather than allowing for auto-negotiation. While this is a simple problem to fix at the OS level (See previous post referred to above), it can become an issue when booting from the PROM.
And, yes, generally, even this issue is easily solved on a machine that's already set up. You can boot up in "100 half," bleeding packets by the truckload, and then set the correct parameters for the network device after logging on. However, if you're trying to install a machine over the net (using Jumpstart, for instance) the out-of-the-gate setting of "100 half" on your network device most likely won't sustain an initial connection to your Jumpstart server, much less an entire install.
Luckily, it is possible to set parameters for your network device at the PROM level. This has saved me more than a few times. There's nothing less enjoyable (unless you're just looking for some "quiet alone time" ;) than having to switch CD's at the console of machine after machine after machine, during an initial server build-out.
Setting up your network interfaces, to comply with the pinned network ports, is also very easy to do. It's so simple, I was surprised the first time I learned how to do it. Like most things with the PROM, exact spelling (characters alpha and numeric) is the difference between success and failure, so it's good to keep this info in your head (or in a crib-sheet). In another previous post we discussed the "sifting" command, which, unfortunately, won't help you much here since the main command we're looking for is "boot." Everything that makes this work is an option to that command.
You can set two properties for the "boot" PROM command that will make all the difference in the world. You can set the "speed" and you can set the "duplex." Oddly enough, those are almost always the exact two things that are giving you a headache ;) So, if you need to connect to your network at "100 full," instead of "boot net - install," you could type in the following:
boot net:speed=100,duplex=full - install <--- Substitute speed and duplex values to your liking.
It's as simple as that. Now you can boot from the PROM and know that your connection is going to be forced to the same speed and duplex that the network admins have pinned the ports to. In a future post, we'll go into how to determine if the "net" devalias isn't pointing to the proper network device in PROM, which devices are active and how to get around that issue.
Barring any other problems, your network install (or just network boot) should now work perfectly :)
, Mike
linux unix internet technology
