Subject: RE: Question on ISTag in ICAP protocol

From: "Martin Stecher" <[email-masked]>
Date: Fri, 30 May 2003 09:50:42 +0200

Yimin,

the standard example for the ISTag motivation is:

A file has been scanned by an ICAP virus scanner. No virus has been detected and the ICAP client stores the file in cache.
Next day the virus scanner engine is updated and it may now be able to find a new virus in the file that has been downloaded the day before.

Changing the ISTag is the way to tell the ICAP client that previous responses that are cached on the client should not be used any longer.

Both, cached ICAP response and cached HTTP object, are invalid.

Regards
Martin

> -----Original Message-----
> From: Yimin Chen [mailto:[email-masked]]
> Sent: Thursday, May 29, 2003 3:20 AM
> To: [email-masked]
> Subject: Question on ISTag in ICAP protocol
> 
> 
> 
> Hi,
> 
> I am reading section 4.7 regarding ISTag in ICAP
> response. In the section, it mentioned that the change
> of ISTag should invalidate all entities generated by a
> particular service. Could someone clarify for me
> whether this "entities" referring to objects in "ICAP
> CACHE" (cache to store ICAP responses), or objects in
> "HTTP CACHE" (in the case that the ICAP client is a
> HTTP proxy. 
> 
> Thanks!
> Yimin 
> 
> __________________________________
> Do you Yahoo!?
> Yahoo! Calendar - Free online calendar with sync to Outlook(TM).
> http://calendar.yahoo.com
> 
> ------------------------------------------------------------
> This mail has been scanned by wwsmtp
> (WebWasher 4.4 beta Build 514)
> ------------------------------------------------------------
>