HTTP HealthCheck monitor with POST Statement

Question

Hello Guys,&nbsp;
We have a couple of Citrix  XML Broker service we want to loadbalance, and we're having problems implementing an advanced http healthcheck monitor.&nbsp;
Basically, its a pool-member specific monitor with a POST statement we tried with curl, like this:&nbsp;
curl -X POST -H 'Content-type: text/xml' -d @broker_monitor.xml http://10.10.10.10:8080/scripts/wpnbr.dll&nbsp;
The content of the broker_monitor.xml file (contains the POST body):&nbsp;

&nbsp;
And here's the response from the server&nbsp;

separate-credentials-validation
      launch-reference
      integrated-authentication
      rade-session-proxy
      multi-image-icons
      user-identity
      full-icon-data
      full-icon-hash
      session-sharing
    
&nbsp;
So, I've written the send string in the monitor like this (minding the quotes and carriage returns)&nbsp;
POST /scripts/wpnbr.dll HTTP/1.1
Host: 10.10.10.10:8080
Content-Type: text/xml

&nbsp;
However, the pool member is marked as down. I don't know what's going on with this ...
Can you see anything wrong?&nbsp;
The version is BIG-IP 11.3.0 Build 3164.0 Hotfix HF10 &nbsp;
Thanks!
Fabian&nbsp;

josiah_39459 · Answer

You can do a tcpdump while the monitor is running and inspect the traffic to verify what you think is being sent is being sent, and what you expect to be returned is being returned.&nbsp;
Alternatively, if you have a curl command that works, you could just use an external monitor and monitor via curl:&nbsp;
https://devcentral.f5.com/wiki/AdvDesignConfig.ExternalMonitor.ashx&nbsp;

dicky_moe_13167 · Answer

Hello Josiah,

We installed wireshark on the node, and captured the requests sent from the F5 monitor and from the server from which we run curl. Here both requests and responses:

Curl Request (as seen from the wireshark capture in the node):

POST /scripts/wpnbr.dll HTTP/1.1
User-Agent: curl/7.19.7 (x86_64-redhat-linux-gnu) libcurl/7.19.7 NSS/3.18 Basic ECC zlib/1.2.3 libidn/1.18 libssh2/1.4.2
Host: 10.10.10.10:8080
Accept: */*
Content-type: text/xml
Content-Length: 169

HTTP/1.1 100 Continue
Server: Citrix Web PN Server
Date: Tue, 05 Apr 2016 16:45:20 GMT

Curl Response:
HTTP/1.1 200 OK
Server: Citrix Web PN Server
Date: Tue, 05 Apr 2016 16:45:20 GMT
Content-type: text/xml
Content-length: 673

F5 request (as seen from wireshark capture in the node)

POST /scripts/wpnbr.dll HTTP/1.1
Host: 10.14.44.118:8080
Content-Type: text/xml

Response to F5 (as seen from wireshark capture in the node)
HTTP/1.1 400 Bad request
Server: Citrix Web PN Server
Date: Tue, 05 Apr 2016 16:40:16 GMT
Connection: Close

As you can see, CURL added some headers that I didn't include (user-agent, content-length, accept).
I tried adding content-lenght, and it didn't work. With or without backslahes count.

Fabian

dicky_moe_13167 · Answer

Hello Josiah,&nbsp;
We installed wireshark on the node, and captured the requests sent from the F5 monitor and from the server from which we run curl. Here both requests and responses:&nbsp;
Curl Request (as seen from the wireshark capture in the node):&nbsp;
POST /scripts/wpnbr.dll HTTP/1.1
User-Agent: curl/7.19.7 (x86_64-redhat-linux-gnu) libcurl/7.19.7 NSS/3.18 Basic ECC zlib/1.2.3 libidn/1.18 libssh2/1.4.2
Host: 10.10.10.10:8080
Accept: /
Content-type: text/xml
Content-Length: 169 &nbsp;
HTTP/1.1 100 Continue
Server: Citrix Web PN Server
Date: Tue, 05 Apr 2016 16:45:20 GMT&nbsp;
Curl Response:
HTTP/1.1 200 OK
Server: Citrix Web PN Server
Date: Tue, 05 Apr 2016 16:45:20 GMT
Content-type: text/xml
Content-length: 673&nbsp;
F5 request (as seen from wireshark capture in the node)&nbsp;
POST /scripts/wpnbr.dll HTTP/1.1
Host: 10.14.44.118:8080
Content-Type: text/xml &nbsp;

&nbsp;
Response to F5 (as seen from wireshark capture in the node)
HTTP/1.1 400 Bad request
Server: Citrix Web PN Server
Date: Tue, 05 Apr 2016 16:40:16 GMT
Connection: Close&nbsp;
As you can see, CURL added some headers that I didn't include (user-agent, content-length, accept).
I tried adding content-lenght, and it didn't work. With or without backslahes count.&nbsp;
Fabian&nbsp;

josiah_39459 · Answer

The host header is different too.  But only your web server logic will tell you why one is good and one is bad (I can't do that).  Otherwise you have to try to make them as close to identical as possible.

dicky_moe_13167 · Answer

The forum deleted some tags because it obviuosly took them as html tags, but the xml in both requests is identical.

I'll try to make the deaders match.

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HTTP HealthCheck monitor with POST Statement

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