Blue Coat SURF-500-999-3YR Manuale Utente

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SurfControl Web Filter v5.5 
Administrator’s Guide
73
R
ULES
 A
DMINISTRATOR
What Objects
7
Filtering IM, P2P and Web Protocols by signature
The Instant Messsaging and Chat (IM) Peer 2 Peer (P2P) and Web Accelerator protocols in the table 
below are port-agile. If a connection fails (for example, due to a disallow rule) on the default port, these 
applications will attempt to use another available port. Enabling Protocol Signature Scanning from the 
Protocol Signatures tab in the Web Filter Settings will ensure that these protocols are filtered when the 
protocols use non-default ports. See 
 for further details.
When adding an Instant Messaging and Chat, Peer to Peer (P2P) or Web Protocol and Port object to a 
rule, the Rules Administrator will only filter the following protocols by signature:
Table 7-4  Signature scanning protocols
P
RECISE
 B
ANDWIDTH
 C
ONTROLS
 O
BJECT
With Precise Bandwidth Control, you can accurately define what content you want to allow or block. By 
creating rules with Precise Bandwidth Controls, you can block pages or files that contain precise prefixes, 
suffixes, or word patterns. These rules operate by identifying the contents within the URL rather than just 
the top level domain name.
Precise Bandwidth Control objects are “if” statements, which means that if you apply more than one 
Precise Bandwidth Control object to a rule, the rule will be triggered when any combination of the objects 
are met. For example, a disallow rule which has precise bandwidth control objects of Audio files and 
Video Files assigned to it, will block an attempt to access web pages that contain audio files or video files 
or both.
Application type
Protocols
Instant Messaging 
MSN Messenger
OSCAR (AIM/ICQ)
XMPP (Jabber)
Peer to Peer (P2P) 
BitTorrent
eDonkey
FastTrack (Kazaa)
Gnutella
Skype
Yahoo! Messenger
Web 
Google Web Accelerator
Note: 
Protocol signature scanning will filter direct HTTP connections and HTTP proxy 
connections. It will not filter when connecting via a SOCKS proxy.
Note: 
If a Category object is assigned to a rule containing Precise Bandwidth Controls, a 
destination will only be blocked if it is within the category AND the URL triggers one or all of 
your Precise Bandwidth Controls.