What is check_http?
5 check_http examples
Syntax and Options
Related Commands
What is check_http?
check_http plugin is used to verify the status of HTTP server (or HTTPS) that is running on a remote host. If you’ve installed Nagios from source, check_httpd command will be located in the /usr/local/nagios/libexec directory.
5 check_http Command Examples
1. Check HTTP
Check whether Apache HTTP is running on a remote server using check_http.
$ check_http -H 192.168.1.50 HTTP OK HTTP/1.1 200 OK - 332 bytes in 0.004 seconds |time=0.004144s;;;0.000000 size=332B;;;0
2. Check HTTPS
Check whether Apache HTTPS is running on a remote server using check_http.
$ check_http -H 192.168.1.50 -S HTTP OK HTTP/1.1 200 OK - 332 bytes in 0.004 seconds |time=0.004144s;;;0.000000 size=332B;;;0
If the remote server runs only HTTP and not HTTPS, you’ll get “HTTP CRITICAL – Unable to open TCP socket” message as shown below.
$ check_http -H 192.168.1.50 -S Connection refused HTTP CRITICAL - Unable to open TCP socket
3. Check HTTP (or HTTPS) on different port
You can check tomcat server, or apache server, or glassfish, or any server that is running on a different port by speficying the port number as shown below.
$ check_http -H 192.168.1.50 -p 8080 HTTP OK HTTP/1.1 200 OK - 332 bytes in 0.004 seconds |time=0.004144s;;;0.000000 size=332B;;;0
For HTTPS running on a different port, do the following.
$ check_http -H 192.168.1.50 -S -p 8443 HTTP OK HTTP/1.1 200 OK - 332 bytes in 0.004 seconds |time=0.004144s;;;0.000000 size=332B;;;0
4. Check Specific URL
To check whether a specific webpage is available, use the -u option as shown below.
$ check_http -H 101hacks.com -u https://linux.101hacks.com/toc
5. Check SSL Certificate Expiry
You can check whether a SSL certificate of the website expires within the next X number of days as shown below. In the following example, we are checking whether the website certificate expires in the next 365 days. The output indicates that it expires in 300 days.
$ check_http -H 101hacks.com -C 365 WARNING - Certificate expires in 300 day(s) (01/01/2011 10:10).
Syntax and Options
check_http -H hostname (or) -I ip-address {optional options}
| Short Option | Long Option | Option Description |
|---|---|---|
| -H | –hostname | host name of the server where HTTP (or HTTPS) daemon is running |
| -I | –IP-address | ip address of the HTTP (or HTTPS) server |
| -p | –port | Port number where HTTP server runs. Default is 80 |
| -4 | –use-ipv4 | This will use IPv4 connection |
| -6 | –use-ipv6 | This will use IPv6 connection |
| -S | –ssl | This will use HTTPS using default 443 port |
| -C | –certificate | Minimum number of days a SSL certiface must be valid. |
| -e | –expect | Expected response string. Default is HTTP/1 |
| -s | –string | Expected content string. |
| -u | –url | URL to check |
| -P | –post | URL encoded http POST data |
| -N | –no-body | Do not wait for whole document body to download. Stop once the headers are downloaded. |
| -M | –max-age | Check whether a document is older than x seconds. Use 5 for 5 seconds, 5m for 5 minutes, 5h for 5 hours, 5d for 5 days. |
| -T | –content-type | Indicate content type in header for POST request |
| -l | –linespan | Regular expression can span to new line (Use this with -r or -R option) |
| -r | –regex, –ereg | Use this regular expression to search for string in the HTTP page |
| -R | –eregi | Same as above, but with ignore case. |
| -a | –authorization | If the site user basic authentication send uid, pwd in the format uid:pwd |
| -A | –useragent | Pass the specified string as “User Agent” in HTTP header. |
| -k | –header | Add additional tags that should be sent in the HTTP header. |
| -L | –link | The output is wrapped as HTML link |
| -f | –onredirect | When a URL is redirected, use this to either follow the URL, or send ok, warning, or critical notification |
| -m | –pagesize | Specify the minimum and maximum page size expected in bytes. Format is minimum:maximum |
| -w | –warning | Response time in seconds for warning state |
| -m | –pagesize | Specify the minimum and maximum page size expected in bytes. Format is minimum:maximum |
| -w | –warning | Response time in seconds for warning state |
| -c | –critical | Response time in seconds for critical state |
| -t | –timeout | Number of seconds to wait before connection times out. Default is 10 seconds |
Related Commands
check_ping
check_ftp
Comments on this entry are closed.
Can i specify what a valid response is, i.e. does the HTML display “xx welcome xx”?
Hello, ask a question, check_http detect page size, page size detection value changes again, the alarm.
Is it possible to check a web page through an authenticated proxy server?
That is superb artile I was looking for! Far better then Nagios documentation.
great! Far better then Nagios documentation.
Dear Friends,
I am gettinr this error in nagios3. can anyone help me out for this problem:-
Check-Website-Response
UNKNOWN 2013-04-25 18:11:24 0d 0h 55m 37s 4/4 RESPONSE: UNKNOWN – ERROR: /usr/bin/nc does does not exist
i am really getting frustrate from this nagios error
nitin: you need to install the netcat package for your distribution which will provide /usr/bin/nc
Thanks for a good article on check_http
I had been using this plugin for a while. But today when I am trying to post an XML message to the server, from console it works well but does not work with nrpe.
It says “Unknown option specified in config file ”
The command is
check_http -I 10.0.0.76 -p 8192 –url=”/MYServiceBus/” –post=”” –eregi=.Status_Code.0./Status_Code. -c 7 -w 5 -v
Any pointer if I am missing anything but obvious.
hello.. I test the command from command line successfull, but when I insert in configuration file (cfg) it gives Error: Service check command ‘check_http -H MYIP -u http://MYIP/test.php‘ specified in service ‘HTTP’ for host ‘Server01’ not defined anywhere!
Here is my configuration :
define service{
use generic-service ; Name of service template to use
host_name Server01
service_description check http://MYIP/test.php
check_command check_http -H MYIP -u http://MYIP/test.php
notifications_enabled 0
}
Would you please be so kind as to help me?
@sunardo – I just ran into this exact same thing. It looks like that with the default install, there’s no configuration set up to tell Icinga where to look for the check_http executable. You need to add the full path to it in the check_command. For example:
check_command /usr/share/nagios/plugins/check_http -H MYIP -u http://MYIP/test.php
Hi,
I Have problem with the check_http when I try ur command test , I have the next message :
check_http: command not found
and nagios show : connection refused
Thank you for your help
JOB,
Try to put full path in the command line. i.e:
/usr/nagios/libexec/check_http …..
Diramos
The -S option is not working with 2.0 plugins. It says -S is for version. How can I get it to work with https with Nagios4 and plugins 2.x?
I am running into the same problem as David
command line output while running with -S is “check_http: Invalid option – SSL is not available”