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Forum Discussion

Jeff_Bull_42197's avatar
Jeff_Bull_42197
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Feb 20, 2015

New monitor looking for a character string is not working

Good morning, I created a new monitor on my LTM which makes an HTTP GET request and looks for a specific string.   Send String: GET /User/MobileSiteStart/List\r\n   Receive String: WAP ...
application delivery
availability
design
LTM
THi's avatar
THi
Icon for Nimbostratus rankNimbostratus
Feb 20, 2015

To clarify why to use this particular syntax:

 

RFC 2616 (Hypertext Transfer Protocol -- HTTP/1.1) states:

 

" A client MUST include a Host header field in all HTTP/1.1 request messages . If the requested URI does not include an Internet host name for the service being requested, then the Host header field MUST be given with an empty value.

 

...

 

All Internet-based HTTP/1.1 servers MUST respond with a 400 (Bad Request) status code to any HTTP/1.1 request message which lacks a Host header field."

 

I have seen that omitting the "Host" header will usually result service "down" and so prefer using the format cjunior proposes. Note the double crlf sequence in the end and also the Connection: Close -header. The exact syntax is dependent upon sw version used. See more on this at: SOL2167: Constructing HTTP requests for use with the HTTP or HTTPS application health monitor