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ib_37889
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May 02, 2012

RAM CACHE header corruption

Hi all,

 

 

I noticed a very strange thing with parts of ram cache headers that seem to get lost ... somehow. I have no idea if it is ltm related or maybe the fact that is is a virtual box or even something totally different.

 

Here is the situation.

 

We have a wp powered site ( single apache backend ) accesible via both a pair of 3600 ltm 10 and a VE running ltm 11.

 

Access via ltm 10, no problem everything works fine.

 

When trying to access the site via the VE , this works fine when served from the backend.

 

When being served from the cache , a browser will ask what to do because the mimetype claims to be "text/htmlt-Ranges"

 

I added log-debug to try to figure it out and started logging headers in both the

 

HTTP_RESPONSE and when CACHE_RESPONSE events.

 

in the CACHE_RESPONSE handler it is printed by

 

 

log local0. "CACHE [ CACHE::headers ] "

 

 

This produces the following output.

 

 

May 2 04:08:26 tmm info tmm[5965]: Rule /Common/spp_cluster : CACHE Server: Apache/2.2.15 (Unix) DAV/2 PHP/5.2.13 X-Powered-By: PHP/5.2.13 X-Pingback: http://www.xxxxxxxxxxxxxxx.com/nl/xmlrpc.php Content-Type: text/html; charset=UTF-8 Accept-Ranges: bytes Connection: Keep-Alive Date: Wed, 02 May 2012 11:08:26 GMT Age: 131 Content-Length: 29286

 

 

I did this request using wget -S to check the returned headers and this produces the following.

 

 

 

HTTP request sent, awaiting response...

 

HTTP/1.1 200 OK Server: Apache/2.2.15 (Unix) DAV/2 PHP/5.2.13

 

X-Powered-By: PHP/5.2.13

 

X-Pingback: http://www.xxxxxxxxxxx.com/nl/xmlrpc.php

 

Content-Type: text/htmlt-Ranges: bytes

 

Connection: Keep-Alive

 

Date: Wed, 02 May 2012 11:08:26 GMT

 

Age: 131

 

Content-Length: 29286

 

X-Ca: bip

 

Length: 29,286 (29K) [text/htmlt-Ranges: bytes] 100%[===========================================================>] 29,286 --.--K/s 13:06:09 (446.84 KB/s) - `index.html' saved [29286/29286]

 

 

The X-Ca: bip header is inserted and the "Accept-Ranges" header (should be ) removed in the CACHE_RESPONSE handler.

 

 

CACHE::header insert X-Ca bip

 

CACHE::header remove "Accept-Ranges"

 

 

It seems that the bold part (marked above) is simply .. gone.

 

 

This behaviour has been confirmed using different browsers/OS's and is 100% reproducable

 

 

Does anyone have a clue what is going on where ?

 

Should someone want to try it, contact me, I'll send the domain

 

Additional info re config/irules on request.

 

 

ib.

 

 

1 Reply

  • Hi ib,

     

     

    If you haven't already, I suggest opening a case with F5 Support. I am guessing this is probably a known issue.

     

     

    Aaron