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Helth Monitor http HTTP/1.1 400 Bad Request


Hello all,


I have built the following monitor:

GET /lexsoft/sgbplus/#default:0 HTTP/1.1\r\nHost: test.test\r\nConnection: Close\r\n\r\n


as return code I expect a 200 OK but get a 400 back


HTTP/1.1 400 Bad RequestDate: Wed, 14 Jul 2021 05:32:30 GMT

Server: Apache/2.4.6 (Red Hat Enterprise Linux)

Content-Length: 226

Connection: close

Content-Type: text/html; charset=iso-8859-1




<title>400 Bad Request</title>


<h1>Bad Request</h1>

<p>Your browser sent a request that this server could not understand.<br />




If I do the following CURL command I get my 200 back

curl -v http://test.test/lexsoft/sgbplus/#default:0


*  Trying test.test...

* Connected to test.test (x.y) port 80 (#0)

> GET /lexsoft/sgbplus/ HTTP/1.1

> Host: test.test

> User-Agent: curl/7.47.1

> Accept: */*


< HTTP/1.1 200 OK


What should my monitor look like to get the desired result? 


Thanks for your help





Legacy Employee
Legacy Employee

Can you please remove "#default:0" from URI of monitor string and give try.


 GET /lexsoft/sgbplus/ HTTP/1.1\r\nHost: test.test\r\nConnection: Close\r\n\r\n


Additionally to  suggestion, take a look at RFC3986:

Notice the # in the URL? It is called a Fragment, typically used to identify a portion of a html document.


This is another example:

It is linking to a headline in the solution page.


I am not exactly sure how health monitors handle the hash mark... Might be your issue.


Have times "#default:0" that deleted.

But has not led to any new result


What is interesting, with two servers that have been in the pool for a while, the check to works as described above. Only with the two new servers I always get the answer 400 back


  The F5 description is about SSL.

For me it is pure HTTP traffic

 I have choosen the link to the F5 solution randomly. I wanted to show you what the hash mark (#) does in a link. The is linking to a specific section in the html document you get from the server.


In your browser, when you open - you will go to the top of subsite one. When you open - you will jump to headline 2 of subsite1.

I am not sure how the monitors of the BIG-IP handle the #.


I tried a little more and deleted the "Connection: Close" now I get a 200 back