ACE Module - HTTP Probe failure

Answered Question
Apr 19th, 2009
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I have configured the http probe with expect status 200 202, but the probe fails despite availability of the port on rserver.

I tried head/get method to see the return code, and it came back with HTTP1.1/302. How can I configure an http probe to understand HTTP 302 code as success return.


Correct Answer by Gilles Dufour about 8 years 2 months ago

under the probe, configure a "header Host www....."


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Gilles Dufour Sun, 04/19/2009 - 21:59
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set the expect status to 302.

If you do a 'show probe detail' what kind of error do you see displayed ?

No. Passed states : 3 No. Failed states : 3

No. Probes skipped : 9 Last status code : 0

No. Out of Sockets : 0 No. Internal error: 0

Last disconnect err : -



cisco_lite Mon, 04/20/2009 - 00:08
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I changed the expect status value as below

probe http TEST-HTTP

interval 30

passdetect interval 10

request method head

expect status 302 302

The probe is still failing with the log message

Apr 20 2009 12:04:35 : %ACE-3-251010: Health probe failed for server on port 80, received invalid status code

On 'show probe detail' it shows the last status code as 400 which means Bad Request

--------------------- probe results --------------------

probe association probed-address probes failed passed health

------------------- ---------------+----------+----------+----------+-------

serverfarm : TEST-APP

real : TEST-SERVER1[80] 27 27 0 FAILED

Socket state : CLOSED

No. Passed states : 0 No. Failed states : 1

No. Probes skipped : 0 Last status code : 400

No. Out of Sockets : 0 No. Internal error: 0

Last disconnect err : Received invalid status code

Last probe time : Mon Apr 20 12:05:33 2009

Last fail time : Mon Apr 20 12:00:53 2009

Last active time : Never

The http page is showing perfectly on the web browser. Also, using the http head/get tool, I can see that 302 is returned.

What could be the problem.


dario.didio Mon, 04/20/2009 - 00:18
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shouldn't you specify the url of the page the ACE should get (head)?

fe: request method head url /index.html

cisco_lite Mon, 04/20/2009 - 01:46
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I have entered request 'request method head url /' which shows in the running config as 'request method head' i.e. default.

Using index.html etc is not mandatory I believe as '/' checks for any web service.

dario.didio Mon, 04/20/2009 - 01:53
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I found this in the config guide for probing:

"By default, the HTTP request method is a GET with the URL “/”. If you do not configure a URL, the probe functions as a TCP probe."

Is your server listening to another port then 80?

cisco_lite Mon, 04/20/2009 - 02:01
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Yes, the service is running. If I do a telnet on port 80 it opens up. The head/get utility is coming back with 302. And the page is showing on the web browser.

cisco_lite Mon, 04/20/2009 - 04:43
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I sniffed the traffic going to the rserver and noticed invalid SYN request to the webserver i.e. I don't see '/' request in the packet capture. Below is the serverfarm config

serverfarm host TEST-APP

rserver TEST-SERVER1 80



However, similar probe is working fine in admin context on another rserver. The only difference is that the probe is on a custom HTTP port and not default port 80. Can that cause a difference.

cisco_lite Mon, 04/20/2009 - 07:24
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To add onto the above, the web server is on IIS 6.0 (Windows Server 2003) and the error returned on the probe is HTTP 400 - Bad Request (Invalid Hostname).

Has anyone experienced this ?

Correct Answer
Gilles Dufour Tue, 04/21/2009 - 06:46
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under the probe, configure a "header Host www....."


paulorosa Thu, 05/21/2009 - 18:56
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I had similar problems with an AS 400.

Had to configure the host.

So I prefere to use the expect 400


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