Network Health

[Thom Little]

I need an persistent application to run on a network to verify that it is
healthy. The concept was to have a Web Application ort Web Service with a
timer that would expire every two minutes and would then verify that all
servers were accessible. If one was found not to be it would send an e-mail
to the support personnel. The timer would then be reset.

Can this actually be done on the "Internet side" as a web application or web
service or must it be packaged as a Windows application on the server? Put
another way, can a persistent server application actually exist in the
absence of the client?

What was the source of your information?

_______________________________________________
Thom Little www.tlanet.net Thom Little Associates, Ltd.

 

[Chad Burggraf]

Can this actually be done on the "Internet side" as a web application or web
service or must it be packaged as a Windows application on the server? Put
another way, can a persistent server application actually exist in the
absence of the client?

I would think not. Web applications are request driven, so that kind of
architecture doesn't make any sense for an application like this. It
would be a very simple Windows Service to write, why not do it that way?

Cheers
Chad

 

[Thom Little]

The customer was envisioning an Internet-side solution and I am wondering if
it is possible.

There is also a question of weather to use Ping or to use the "try to load a
tiny gif image" approach to determine if the servers external to the one
running the program are operational. Apparently not all servers support
Ping?

_______________________________________________
Thom Little www.tlanet.net Thom Little Associates, Ltd.

 

[Chad Burggraf]

The customer was envisioning an Internet-side solution and I am wondering if
it is possible.

There is also a question of weather to use Ping or to use the "try to load a
tiny gif image" approach to determine if the servers external to the one
running the program are operational. Apparently not all servers support
Ping?

Does the customer care about a Web-based solution because of how it's
managed or for some other reason? I would assume that you would log the
status of your service (if implemented as a service) somewhere (i.e. a
database or on the file system), so having a Web application interact
with that would be a good solution. You could also of course use a Web
application to perform on-demand status updates or to turn off the
service or whatever.

As far as ping goes, it would be fine for an intranet where you have
control over your servers. In the wild though you'd have to do some
other sort of test. If you have POP or Web servers running on the remote
machines you could do a simple response-based test. It all depends on
your situation.

Cheers
Chad

 

[DeveloperX]

Yep, ping simply means sending an ICMP packet to the remote server, and
every machine implementing TCP/IP supports ICMP. These are often
blocked by firewalls, and anyway won't tell you if the web server (I
assume that's what you're monitoring) is running on the server.
As Chad says, a web server responds to events, so a service is really
the way to go. There's no reason the service can't use the web server
to send emails though, and a web app could communicate with the service
to provide web based reporting, although it might be easier having the
service log to a database and feed the web app from there. That will
give you some sort of historic data that may be useful.
Rather than check for a specific file on the server, it might be easier
just to try and establish an http connection. If that works you should
be ok.
Finally when you say the customer wants "an internet-side solution" do
you mean they want it to run out in the wild on an internet side web
server? It depends on how much access you have to the internet server,
but if it has SQL server on it, you can use sql agent running a job on
a schedule that could query a web page on your website which will then
check the other web servers (looking for the least invasive options).

 

[Thom Little]

I am now testing the connection to each host on its port 80.

The customer issue was a semantics problem using the universally overused
and ambiguous terms ... server, client, windows, and Internet.

Thanks to both of you for your help.

_______________________________________________
Thom Little www.tlanet.net Thom Little Associates, Ltd.