Cisco Cisco Web Security Appliance S690 Guía Del Usuario

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AsyncOS 10.0 for Cisco Web Security Appliances User Guide
 
Chapter 10      Create Policies to Control Internet Requests
  Time Ranges and Quotas
Time and Volume Quotas
Quotas allow individual users to continue accessing an Internet resource (or a class of Internet resources) 
until they exhaust the data volume or time limit imposed. AsyncOS enforces defined quotas on HTTP, 
HTTPS and FTP traffic. 
As a user approaches either their time or volume quota, AsyncOS displays first a warning, and then a 
block page. 
Please note the following regarding use of time and volume quotas:
If AsyncOS is deployed in transparent mode and HTTPS proxy is disabled, there is no listening on 
port 443, and requests are dropped. This is standard behavior. If AsyncOS is deployed in explicit 
mode, you can set quotas in your access policies.
When HTTPS proxy is enabled, possible actions on a request are pass-through, decrypt, drop, or 
monitor. Overall, quotas in decryption policies are applicable only to the pass-through categories.
With pass-through, you will also have the option to set quotas for tunnel traffic. With decrypt, this 
option is not available, as the quotas configured in the access policy will be applied to decrypted traffic.
If URL Filtering is disabled or if its feature key is unavailable, AsyncOS cannot identify the category 
of a URL, and the Access Policy -> URL Filtering page is disabled. Thus, the feature key needs to 
be present, and Acceptable Use Policies enabled, to configure quotas..
Many websites such as Facebook and Gmail auto-update at frequent intervals. If such a website is 
left open in an unused browser window or tab, it will continue to consume the user’s quota of time 
and volume.
A proxy restart will cause quotas to be reset, potentially allowing much more access than planned. 
A proxy restart may occur because of a configuration change, a crash, a machine reboot, and so on. 
Some confusion is possible, as administrators are not explicitly informed about proxy restarts.
Your EUN pages (both warning and block) cannot be displayed for HTTPS even when 
decrypt-for-EUN option is enabled.
Note
The most restrictive quota will always apply when more than one quota applies to any given user.
Volume Quota Calculations
Calculation of volume quotas is as follows:
HTTP and decrypted HTTPS traffic – The HTTP request and response body are counted toward 
quota limits. The request headers and response headers will not be counted toward the limits. 
Tunnel traffic (including tunneled HTTPS) – AsyncOS simply shuttles the tunneled traffic from the 
client to the server, and vice versa. The entire data volume of the tunnel traffic is counted toward 
quota limits.
FTP – The control-connection traffic is not counted. The size of the file uploaded and downloaded 
is counted toward quota limits.