How to monitor web sites properly via Nagios

Hi Experts,

We have an issue with Nagios at the moment attempting to monitor Web sites.

Nagios reports as ok if port 80 is open - if the site is parked, Nagios wouldn't know.

Is there a better solution to check if the website is down or changed?

Can you monitor a particular picture or text in the site?

Perhaps a more powerful plugin is available?

Please help...
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jeremycrussellConnect With a Mentor Commented:
To add to hfraser's response... To check for an image, just use the --string reponse and check for the image path/name

i.e  check_http -H host --string "/path/to/images/image.jpg"
Hugh FraserConnect With a Mentor ConsultantCommented:
The check_http plugin allows you to search the content for a specific string (--string) or regular expression (--regex or --eregi). If the site is a secure site (SSL), you can check for a valid certificate. Finally, you can check to see if the page is re-directed.
bossagroupAuthor Commented:
so can a specific string be a image on the webpage?

If so can you please show me the command to use?
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Hugh FraserConnect With a Mentor ConsultantCommented:
The check_http command can look for any string in the content of a web page. For example, the command:

check_http --string "Welcome to my site" mywebsite.,com -u welcome.html

would check for the string "Welcome to my web site" on

This plugin is designed to search the entire content of a web page (including mime-encoded image files) for a specific string, but not well suited to tell if the web page has changed in any way. If you want to do this, you could do a simple check to see if the page size has changed (check_http -m min:max) or write a simple script to compare an md5 hash of the image file.

Hugh FraserConsultantCommented:
Checking for a change to a link to an included image file isn't the same as checking for a change to the image file itself (ie. it's a different image). But it depends upon what you want to check.
bossagroupAuthor Commented:
Thanks guys,

Exactly what I was after!
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