Nagios Support Forum

when I use check_http -I IP_address -p 50075 -v -N -L, I get
<A HREF="http://IP_address:50075/" target="_blank">GET / HTTP/1.0
User-Agent: check_http/v2.0.3 (nagios-plugins 2.0.3)
Connection: close
Accept: */*


http://IP_address:50075/ is 70 characters
STATUS: HTTP/1.1 400 Bad Request
**** HEADER ****
Connection: close
Server: Jetty(6.1.26)
**** CONTENT ****
[[ skipped ]]
HTTP WARNING: HTTP/1.1 400 Bad Request - 70 bytes in 0.010 second response time </A>|time=0.010237s;;;0.000000 size=70B;;;0

but if I use hostname for the same host, I get HTTP /OK status. I am not sure what is happening.. Any pointers

It sounds like there is a virtualhost setup, which is expecting the DNS name and not the IP. You'll want to use the hostname for the check.