Akamai Pragma Debug Headers

If you are using Akamai service, most of the time you will need to check the cached object validity or the traffic behavior. For Akamai service, adding in some specific Pragma headers will give you the useful information you need during troubleshooting.

Akamai has the useful extension/add-on in Firefox and IE that can append Akamai specific Pragma headers automatically, and in response you will be able to see those useful Akamai information for debugging purpose. If you are Akamai user, you can download EdgeSuite Booster in EdgeControl portal -> Site Accelerator -> Tools -> Development Tools.

Once EdgeSuite Booster gets installed, the process is automated. Open an Akamai site in Firefox will return you the useful information in Firebug console. Take notice on the request Pragma headers, and the response headers start with “X-” below.

Request Headers

Accept	                text/css,*/*;q=0.1
Accept-Encoding	        gzip, deflate
Accept-Language	        en-us,en;q=0.5
Cache-Control	        no-cache
Connection	        keep-alive
Host	                www.website.com
Pragma	                akamai-x-cache-on, akamai-x-cache-remote-on, 
                        akamai-x-check-cacheable, akamai-x-get-cache-key, 
                        akamai-x-get-extracted-values, akamai-x-get-nonces, 
                        akamai-x-get-true-cache-key, akamai-x-serial-no
User-Agent	        Mozilla/5.0 (Windows NT 6.1; rv:11.0) Gecko/20100101 Firefox/11.0

Response Headers

Cache-Control           private, max-age=1103
Connection	        keep-alive
Content-Encoding	gzip
Content-Length	        9120
Content-Type	        text/css
Date	                Sun, 18 Mar 2012 10:59:33 GMT
Etag	                W/"34608-1330928498000"
Last-Modified	        Mon, 05 Mar 2012 06:21:38 GMT
Server	                Apache-Coyote/1.1
Vary	                Accept-Encoding
X-Akamai-Session-Info	name=PARENT_SETTING; value=TD
X-Cache	                TCP_MEM_HIT from a118-214-191-15 (AkamaiGHost/
X-Cache-Key	        /L/1745/15811/3h/www.website.com/common/css/style.css
X-Check-Cacheable	YES
X-Serial	        1745
X-True-Cache-Key	/L/www.website.com/common/css/style.css
ntCoent-Length	        34608

Explanation on some of the Akamai debug headers.

X-Cache : Cache State

X-Cache	               TCP_MEM_HIT from a118-214-191-15 (AkamaiGHost/
a118-214-191-15      : Akamai IP Identifier (The Akamai server that serves this request)
TCP_HIT              : The object was fresh in cache and object from disk cache.
TCP_MISS             : The object was not in cache, server fetched object from origin.
TCP_REFRESH_HIT      : The object was stale in cache and we successfully refreshed with 
                       the origin on an If-modified-Since request.
TCP_REFRESH_MISS     : Object was stale in cache and refresh obtained a new object from 
                       origin in response to our IF-Modified-Since request.
TCP_REFRESH_FAIL_HIT : Object was stale in cache and we failed on refresh (couldn't 
                       reach origin) so we served the stale object.
TCP_IMS_HIT          : IF-Modified-Since request from client and object was fresh in
                       cache and served.
TCP_NEGATIVE_HIT     : Object previously returned a "not found" (or any other negatively
                       cacheable response) and that cached response was a hit for this
                       new request.
TCP_MEM_HIT          : Object was on disk and in the memory cache. Server served it 
                       without hitting the disk.
TCP_DENIED           : Denied access to the client for whatever reason.
TCP_COOKIE_DENY      : Denied access on cookie authentication (if centralized or 
                       decentralized authorization feature is being used in config).

X-Cache-Key : Internal Cache Key

X-Cache-Key	  /L/1745/15811/3h/www.website.com/common/css/style.css
15811           : Akamai CP Code
3h              : Cache TTL
www.website.com : Origin Server Name

X-Check-Cacheable : Cacheability

This determines if the request object is cache-able as set in your Akamai configuration.

Other Tools to get Akamai Debug Headers

If you do not have the access to EdgeControl portal to download the EdgeSuite Booster. You can use “curl” or Fiddler2 to do the same job for you.

Using curl

curl -I -H "Pragma: akamai-x-cache-on, akamai-x-cache-remote-on, 
akamai-x-check-cacheable, akamai-x-get-cache-key, akamai-x-get-extracted-values, 
akamai-x-get-nonces, akamai-x-get-ssl-client-session-id, akamai-x-get-true-cache-key, 
akamai-x-serial-no" http://www.website.com/style.css

Using Fiddler2

Open Fiddler2, follow below steps.

You will be able to see the Akamai debug headers in Fiddler2 inspector.

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5 Responses to “Akamai Pragma Debug Headers”

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  1. The URL to the firefox plugin at Akamai is:

    Looks like they’ve updated it for newer versions of Firefox.

  2. Pingback: Ian Winter » Blog Archive » CDN Debugging

  3. And options for reviewing the responses are:

    1. Live Headers

    2. HTTP Fox

    3. And one I love for doing a lot more; Tamper Data

  4. Thanks this article is very helpful……

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